News about Teletypes and similar mechanical teleprinting terminals ////////////////////////////////////////////////////////////////////////////// Newsgroups: comp.terminals NNTP-Posting-Host: 81.106.167.191 NNTP-Posting-Date: Sat, 04 Jul 2009 01:27:28 UTC References: Message-ID: <4ey3m.15129$rO.1893@newsfe13.ams2> Organization: virginmedia.com Date: Sat, 04 Jul 2009 02:26:06 +0100 From: Paul Potter Subject: Re: Why putty? Keith F. Lynch wrote: > > Stephen Jones wrote: >> >> Anyone use real TTYs? Like this: >> >> http://www.youtube.com/watch?v=Ml00ngVwrcU >> >> Now thats a TTY .. > > I have no idea what's at that URL. I read the net on a DEC VT420 > terminal, and it doesn't do video. I like your old school way of doing it. ////////////////////////////////////////////////////////////////////////////// Newsgroups: comp.terminals NNTP-Posting-Date: Fri, 22 Feb 2008 01:15:03 +0000 (UTC) References: Message-ID: Organization: multi-cellular, biological Date: Fri, 22 Feb 2008 01:15:03 +0000 (UTC) From: Richard Subject: Re: sources for Teletypes John spake the secret code thusly: > > I'm looking for a ASR 33 or ASR 35 Teletype to put in the office here > at work... anybody have some recommendations on where to find one? > San Francisco area is preferable but anywhere is fine. They come up on eBay periodically and sell for anywhere between a couple hundred and several thousand dollars, depending on condition and accessories. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download ////////////////////////////////////////////////////////////////////////////// 1996 address listing Teletype Corporation 5555 Touhy Ave. Skokie, IL 60077-3235 USA Phone: +1 847/677-0800 .............................................................................. As of early A.D. 2004, commentary on the Teletype Model ASR33 printing terminal may be viewed here: http://www.pdp8.net/asr33/asr33.shtml .............................................................................. Newsgroups: comp.dcom.telecom Path: utkcs2!gatech!darwin.sura.net!udel!wupost!spool.mu.edu!telecom-request Message-ID: Sender: Telecom@eecs.nwu.edu Organization: University of California, Santa Cruz Lines: 207 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 938, Message 2 of 6 Date: 17 Nov 1991 08:34:46 GMT From: haynes@cats.UCSC.EDU (Jim Haynes) Subject: History of Teletypewriter Development Here's another one (and that exhausts my supply). These two came into my hands as Monographs when I was working for Teletype in 1963-1966. The main reason I typed them in is to get them into the telecom archive since they contain information that isn't readily available so far as I know. HISTORY OF TELETYPEWRITER DEVELOPMENT R. A. Nelson K. M. Lovitt, Editor October 1963 Teletype Corporation 5555 West Touhy Avenue Skokie, Illinois ------ ABSTRACT The success of the modern teletypewriter began with Howard L. Krum's conception of the start-stop method of synchronization for permutation code telegraph systems. The purpose of this paper is to provide a brief historical account of events which led to that achievement and of those which ensued. Four areas of development will be covered: (1) The contributions of Sterling Morton, Charles L. Krum and Howard L. Krum. (2) The contributions of E. E. Kleinschmidt. (3) The contributions of AT&T and Western Electric. (4) The contributions of L. M. Potts ----- _HISTORY OF TELETYPEWRITER DEVELOPMENT_ Area I. In 1902 a young electrical engineer named Frank Pearne solicited financial support from Joy Morton, head of the Morton Salt interests. Pearne had been experimenting with a printing telegraph system and needed sponsorship to continue his work. Morton discussed the matter with his friend, Charles L. Krum, a distinguished mechanical engineer and vice president of the Western Cold Storage Company (which was operated by Joy's brother, Mark Morton). The verdict for Pearne was favorable, and he was given laboratory space in the attic of the Western Cold Storage Company. After about a year of unsuccessful experimenting, Pearne lost interest and decided to enter the teaching field. Charles Krum continued the work and by 1906 had developed a promising model. In that year his son, Howard, a newly graduated electrical engineer, plunged into the work alongside his father. The fruit of these early efforts was a typebar page printer (Patent No. 888,335; filed August 22, 1903; issued May 19, 1908) and a typewheel printing telegraph machine (Patent No. 862,402; filed August 6, 1904; issued August 6, 1907). Neither of these machines used a permutation code. They experimented with transmitters as well, applications filed in 1904 and 1906 maturing into Patents No. 929,602 and No. 929,603. These patents covered modes of transmission which depended both on alternation of polarity and change in current level. By 1908 the Krums were able to test an experimental printer on an actual telegraph line. The typing portion of this machine was a modified Oliver typewriter mounted on a desk with the necessary relays, contacts, magnets, and interconnecting wires (Patent No. 1,137,146; filed February 4, 1909; issued April 27, 1915). As a result of the successful test of this printer, Charles and Howard Krum continued their experiments with a view to developing a direct keyboard typewheel printer. They sought most of all to discover a way of synchronizing transmitting and receiving units so that they would stay "in step." It was Howard Krum who worked out the start-stop method of synchronization (Patent No. 1,286,351; filed May 31, 1910; issued December 3, 1918). This achievement, which more than anything else put printing telegraphy on a practical basis, was first embodied (for commercial purposes) in the "Green Code" Printer, a typewheel page printer (Patent No. 1,232,045; filed November 28, 1909;issued July 3, 1917). The transmitters first used by the Krums were of the continuously- moving-tape variety. (A stepped tape feed, they maintained, would have reduced transmission speed.) In order to permit sequential sensing, the rows of code holes were arranged in a slightly oblique pattern (with respect to tape edges). This method of transmission is more fully elaborated in Krum Patents No. 1,326,456, No. 1,360,231, and No. 1,366,812. Keyboard-controlled cam-type start-stop permutation code transmitters were developed by Charles and Howard Krum in about 1919. Such a device is the transmitter component of the Morkrum 11-Type tape printer (Krum Patent No. 1,635,486). This kind of transmitter employs a single contact to open or close the signal line. In about 1924 the Morkrum Company introduced the No. 12-Type tape printer (H. L. Krum Patent No. 1,665,594). On December 23, 1924, Howard Krum and Sterling Morton (son of Joy Morton) filed an application on the 14-Type type-bar tape printer which matured into Patent No. 1,745,633. [1] Area II. It appears that the early efforts of E. E. Kleinschmidt were directed toward development of facsimile printing apparatus and automatic Morse code equipment. He patented first a Morse keyboard transmitter (Patent No. 964,372; filed February 7, 1095; issued January 11, 1910) and later a Morse keyboard perforator (Patents No. 1,045,855, No. 1,085,984, and No. 1,085,985). (The latter became known as the Wheatstone Perforator.) In 1916 Kleinschmidt filed an application for a type-bar page printer (Patent No. 1,448,750 issued March 20, 1923). This printer utilized Baudot code but was not start-stop. It was intended for use on multiplex circuits, and its printing was controlled from a local segment on a receiving distributor of the sunflower type. Later, around 1919, Kleinschmidt appeared to be concerned chiefly with development of multiplex transmitters for use with this printer (Kleinschmidt Patent No. 1,460,357). It seems that Kleinschmidt first became interested in modern start-stop permutation code telegraph systems when H. L. Krum's basic start-stop patent was issued in December 1918. Shortly after that Kleinschmidt filed an application entitled "Method of and Apparatus for Operating Printing Telegraphs" (Patent No. 1,463,136; filed May 1, 1919; issued July 24, 1923). The system described therein employed the start-stop principle with a modified version of his earlier multiplex distributor. That patent, accordingly, was dominated by the Krum start-stop patent. The conflict of patent rights between the Morkrum Company and the Kleinschmidt Electric Company eventually led to a merger of the two interests. Shortly after the new Morkrum-Kleinschmidt Corporation (later called the Teletype Corporation) had been established, Sterling Morton, Howard Krum, and E. E. Kleinschmidt filed an application covering the commercial form of the well-known 15-Type page printer (Patent No. 1,9904,164). [2] Area III. Teletype entered the Bell System in 1930. From this point on, advances in the Teletype product can be considered the result of the pooled efforts of the AT&T Company, the Western Electric Company, and the Teletype Corporation. Teletype Corporation, of course, holder of the basic patents and expert in the art, was the chief contributor. Although it appears from the report of R. E. Pierce, dated December 24, 1934, that the Bell System was active in the development of telegraph printers and transmitters as early as the year 1909, a review of the patents issued to Bell reveals no significant contribution to modern teletypewriter development (using start-stop permutation code) until the introduction in 1920 of the 10-A teletypewriter (Pfannenstiehl Patents No. 1,374,606, No. 1,399,933, No. 1,426,768, No. 1,623,809, and No. 1,661,012). The 10-A teletypewriter was the first embodiment of such basic design features of the 15-Type printer as stationary platen, moving type basket, and selector vane assembly, but the majority of improvements incorporated in the 15-Type were proprietary to the Teletype Corporation. Area IV. The earliest contribution of Dr. L. M. Potts to the start-stop method of synchronization appears to have been set forth in a patent application filed November 18, 1911, covering a reed-type start-stop selector (Patent No. 1,151,216). In 1914, Dr. Potts filed an application for a single magnet page printer which used an eight-unit code (Patent No. 1,229,202; issued June 5, 1917). In 1915, Dr. Potts filed an application covering another single magnet page printer, this one using the start-stop permutation code (Patent No. 1,370,669; assigned to AT&T March 8, 1921). Potts Patents No. 1,517,381 and No. 1,570,923 were also assigned to AT&T. ---------- [1] For anyone who is old enough to have seen a Western Union Telegram where the typing is on narrow gum-backed tape that is moistened and stuck to a telegram blank, this is the machine that produces that kind of printing. The same mechanism is the basis of a typing reperforator, a machine which punches received signals into a tape for retransmission and also types on the tape so an operator can read it. [2] This is the machine used until the 1960s or so by the news wire services. Some radio stations still use a recording of the sound of one of these machines as background during news broadcasts. haynes@cats.ucsc.edu haynes@cats.bitnet [Moderator's Note: Thank you for two very excellent articles this weekend on the history of Teletype and its predecessor companies. Jim's earlier article on the history of the Morkrum Company was distributed as a special mailing sent out between issues 936-937 on Saturday evening. Watch for your copy to arrive if it hasn't yet. But I am curious about something not mentioned in either article. Did the Bell System buy out Morkrum and change the name to Teletype in 1930 or did Teletype start and later buy out Morkrum? How did that transition occur? I love these history articles because so much telecom history happened right here in Chicago -- the Chicago I like to remember from years ago. PAT] ////////////////////////////////////////////////////////////////////////////// Article 22297 of comp.dcom.telecom: Path: utkcs2!gatech!asuvax!cs.utexas.edu!swrinde!mips!pacbell.com!lll-winken!telecom-request From: haynes@cats.UCSC.EDU (Jim Haynes) Newsgroups: comp.dcom.telecom Subject: Re: History of Teletypewriter Development Message-ID: Date: 19 Nov 1991 06:09:57 GMT Sender: Telecom@eecs.nwu.edu Organization: TELECOM Digest Lines: 10 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 947, Message 7 of 12 > From cmoore@BRL.MIL Mon Nov 18 08:30:01 1991 > To: Jim Haynes > Among the patents in the message about Teletype is this one: > 15-Type page printer 1,9904,164 [sic] > Is there a type of some sort in this patent number? Yes, there is a typo. The patent number should be 1,904,164. ////////////////////////////////////////////////////////////////////////////// Newsgroups: comp.dcom.telecom Path: utkcs2!ornl!rsg1.er.usgs.gov!ukma!asuvax!cs.utexas.edu!qt.cs.utexas.edu !zaphod.mps.ohio-state.edu!uwm.edu!lll-winken!telecom-request Message-ID: Sender: Telecom@eecs.nwu.edu Reply-To: sjl@glenbrook.com Organization: Glenbrook Systems, Inc. Lines: 141 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 1026, Message 1 of 9 Date: 18 Dec 1991 05:52:32 GMT From: sjl@glensjl.glenbrook.com (Scott Loftesness) Subject: AT&T Exits Telegraph Business [Moderator's Note: The end of an era! Thanks also to Alan Toscano for sending this AT&T press release. PAT] BASKING RIDGE, N.J. -- Familiar to the world over through the clickety-clack of ticker tape machines and teletypewriters, telegraphy has been gradually bowing out of the telecommunications picture during the last twenty years. The nonstop chatter has been replaced by the hum of laser printers and the electronic beeps on computer screens. AT&T, a leading innovator and major service provider of telegraphy, announced this year it is withdrawing the service due to the universal availability of lower-cost, higher quality digital telecommunications services. "The incredible advances in our industry means customers can get more for less," said Wes Bartlett, AT&T district manager, Business Communications Services. "Today's digital technology can transmit information hundreds of thousands times faster than telegraphy and is considerably more cost-effective for users. "Telegraphy has been to the twentieth century what state-of-the-art digital telecommunications services will be to the next century," Bartlett added. "We are proud of our contributions in both areas." The transmission of telegraph service is based on analog technology, which sends information by continuous electrical waves. Today's digital technology breaks information into its smallest components, the binary "ones and zeros" of computer language. However, telegraphy was the actually the first digital service -- although a very simplified version compared with today's technology -- since it was produced on the customer's premises in terms of "on or off," or "dash or space." It was converted to analog for transmission. Telegraphy usage accelerated rapidly during the 1920s when the financial industry adopted the technology to send records of transactions. At this time, news organizations began using telegraph service for transmitting stories between offices. In November, 1931 the Bell System inaugurated the teletypewriter exchange service, often called the TWX (pronounced "twicks") service. It provided a complete communications system for the written word, including teletypewriters, transmission channels and switchboards. Telegraphy was adopted by many kinds of businesses, including utility companies, alarm companies, airlines, and brokerages as well as government agencies. It was used heavily through the 1960s. Most of AT&T's telegraph service customers have been converted to digital private line services such as DATAPHONE (R) Digital Service and ACCUNET (R) Spectrum of Digital Services. "Our name remains American Telephone and Telegraph," Bartlett said. "It is an historic name and our legacy. We are proud to have a corporate name that spans generations of communications technology. "Despite rapid technological change, AT&T remains focused on helping people communicate," Bartlett added. "Telegraphy helped bring us to this point. Digital technology is taking us into a new era of global messaging." ### Background WHAT WAS TELEGRAPH SERVICE? Telegraph service made it possible to communicate large volumes of information between two or more locations. Telegraph circuits permitted customers to send to each other a printed or hard copy version of the information at reasonable cost, which was impractical with the telephone. A telegraph circuit consisted of four components: station equipment installed on the customer's premises, such as a teletypwriter and teleprinter; the local loop, or wires, between the customer location and the AT&T central office; the central office equipment in the AT&T telegraph serving test center (STC); and the wires connected to the telegraph STC serving the other customer. Here's how it worked: Customer A sent information to customer B by typing the information on a teletypewriter keyboard. The teletypewriter converted the message to a coded signal which was sent out on the local loop to the STC and central office equipment. There the signal was converted to make it compatible with the carrier's lines and sent on to the STC serving the distant city. The central office equipment then converted the signal again and sent it over the local loop to customer B's teletypewriter which decoded the signal and printed the information. The procedure was reversed if customer B wanted to send information to customer A. This method of sending information, where only one station could send at a time, was accomplished over a simple half-duplex, or two-wire circuit. When both customers wanted to send and receive at the same time a full-duplex, or four-wire circuit, was used. At its peak in 1970, telegraph service could transmit data at 150 bits per second. ### AT&T and Telegraph Service 1887: First private-line telegraph service, for L. H. Taylor & Co., brokers, between their offices in New York and Philadelphia. 1888: First service for news media customer, Globe Newspaper Company, between New York and Boston. 1915: Teletype offers speeds of 30 or 50 words per minute. 1920s: Press and financial markets create a boom for usage of the service. 1939: Speed reaches 75 words per minute. 1944: Speed reaches 100 words per minute. 1957: Teleprinter introduces speeds of 300 words per minute. 1970s: Decline in usage begins as electronic data processing replaces many telegraph functions. 1980s: Wireless and digital methods accelerate decline. 1991: AT&T exits telegraph service. ### Scott Loftesness Internet: sjl@glenbrook.com 515 Buena Vista Avenue Others: 3801143@mcimail.com Redwood City, CA 94061 76703.407@compuserve.com ////////////////////////////////////////////////////////////////////////////// Newsgroups: comp.dcom.telecom Path: cs.utk.edu!darwin.sura.net!newsserver.jvnc.net!howland.reston.ans.net !spool.mu.edu!telecom-request Message-ID: Organization: TELECOM Digest Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 13, Issue 149, Message 1 of 5 Date: Tue, 2 Mar 1993 14:26:39 -0800 From: haynes@cats.UCSC.EDU (Jim Haynes) Subject: A Little More TWX History Well of course the original TWX goes back to about 1930, used 3-row machines, and manual switchboards. In fact the introduction of TWX was what caused AT&T to buy the Morkrum-Kleinschmidt Corp. and rename it Teletype. At the time the service was provided using telegraph-grade circuits. You'll occasionally see a picture of an old TWX switchboard, maybe in an old encyclopedia. The switchboard operators used tape-strip printers to communicate with the customers. Telex was in use in Europe in about the same time frame, and used SXS switching technology and telegraph-grade circuits. Western Union introduced Telex to the U.S. in the early 60s. This was probably a bad mistake for them. 1) They had to buy a lot of electromechanical switching equipment which was soon to be obsoleted by electronic switching. 2) AT&T was about to move TWX to the voice switched network, where the enormous volume of voice service had driven the cost of connections and bandwidth way down. The telegraph-grade lines were no longer cheaper than voice circuits; they were in fact more costly to AT&T. 3) It put W.U. into practically head-to-head competition with an AT&T service; and AT&T was a much stronger company financially. 4) W.U. was usually dependent on the telephone companies for local loops between customers' offices and the nearest W.U. office. Thus W.U. was at the mercy of its competitors rates for these private lines. As an aside, European Baudot machines tended to have four-row keyboards. The digits were on the fourth row, like a typewriter. There were blocking bars such that if the machine was in FIGS case the digit keys were unblocked and the corresponding letters keys were blocked. So the user still had to send FIGS and LTRS as in the U.S.; it was just that the European machine design took a slightly different direction from that in the U.S. The European machines also tended to have built-in paper tape facilities of the limited sort that Teletype introduced into the Model 32 and 33 machines. In previous Teletype designs the paper tape equipment was mechanically independent of the keyboard and printer. You could, for instance, be punching a tape from the keyboard at the same time you were receiving a message on the printer; and you could be sending from tape at the same time you were punching another tape from the keyboard. In the European machines, and later in the Teletype 32 and 33, the tape punch had some parts in common with the printer and the tape reader shared some parts with the keyboard. Hence you couldn't use the keyboard while sending from tape; you couldn't punch a tape from the keyboard while printing something else, etc. The Teletype Model 15 has been mentioned as a heavy-duty machine dating from 1930. In the late 1930s some of the Bell companies asked for a less expensive machine for TWX service, recognizing that a lot of offices could use TWX but didn't need the heavy-duty machine. (The Model 15 is what was used for AP and UP news wires through the 1950s. It could stand up to the around-the-clock printing that occurs in that service.) The answer to this request was the Model 26. The 26 used a rotating type cylinder holding individual slugs of type. The cylinder stayed in one place and the paper platen moved from side to side as in a typewriter. (In the Model 15 and the later machines the paper platen is stationary and the printing element moves across the page.) The Bell System phased out the Model 26 machines in, oh, the late 40s and 50s. The machine didn't save enough in first cost to be worth supporting both it and the Model 15 in terms of parts and maintenance training. Lots of Model 26 machines wound up in amateur radio service. The hams formed organizations to plead with the Bell companies to sell their used machines to hams rather than breaking them up (to prevent their falling into the hands of those who would use them in competition with Bell services). Hams had to sign a legal form to the effect that they would not use the machine outside the hobby, and would not sell it to anyone without requiring a similar promise. In the late 50s and early 60s came all the work that resulted in ASCII -- first the upper-case-only 1961 ASCII and then the up/low 1968 ASCII. Prior to ASCII there were lots of codes floating around. Teletype made the Model 29, which was an eight-level four-row machine working on one of the IBM BCD codes. I believe this was used only internally in Western Electric; AT&T was scared to put an IBM coded machine out to the public lest non-IBM computer makers complain that the AT&T giant was favoring the IBM giant at their expense. The Model 35 was based on the 29; in fact I'm aware of some people converting 29 printers to ASCII by changing just a few parts. Many parts were common between the five-level Model 28 and the eight-level Model 35. The Model 32 and 33 machines actually started as a project to develop a light-weight machine for the military. The light-weight project didn't get very far; but a lot of the ideas wound up being used in the low-cost printer project. Again the Bell companies and Western Union saw a need for a machine that would cost a lot less than the heavy-duty machines, for use in offices that didn't have a lot of traffic. I might mention that Western Union dabbled in making its own teleprinters from time to time; occasionally one will see a sample of their Model 100 family. I believe W.U. was the main customer for the 32, for Telex service and the Bell companies were seen to be the main customers for the 33 for the new four-row dial TWX service. These machines had most of the parts in common. They were available with and without paper tape; where paper tape was present it followed the European style, so you couldn't do all the things with these machines that you could with a 28 or 35. The design objective for the 32 and 33 was that they would be used on an average two hours per day. Cost was held down by not heat treating and hardening and nickel plating the parts; some adjustments were made by bending parts rather than by moving parts on elongated holes and that sort of thing; assembly was designed for high volume with a die cast base and self-tapping screws and parts that snapped together without bolting. Meanwhile along came the minicomputer companies who adopted the 33 as a console device, where it often ran around the clock (and generated a lot of cursing about the frequent need for maintenance). For manual TWX Teletype supplied a basic machine to the phone company, which added some kind of Western Electric box on the wall for line interface. This might be a carrier channel terminal or some relays for a D.C. line; and there were schemes where ringing was used to control the motor on the Teletype machine, and schemes for cutting off current in the line when it was not in use. Telex and dial TWX required additional components for setting up and controlling the call. The Model 32 for Telex had a built-in Call Control Unit with a dial and line relays, all ready to connect to the D.C. local loop. For dial TWX there was a Western Electric modem stashed in the Teletype stand and a variety of call control units (pulse dial, tone dial, card dialer, loudspeaker vs. earphone, etc.) made by Teletype and connecting to the modem. This was a source of considerable annoyance to Teletype, as the interface involved 99 wires, each of which was negotiated between the modem designers at Bell Labs and the call control unit designers at Teletype. A little later some of the Bell companies would save money by furnishing a Bell modem with built-in telephone connecting over a few-wire cable to a Teletype private-line-version machine having no call control unit. There is a lot of weird and interesting (perhaps) lore connected with the modems. Since dial TWX used a voice-bandwidth connection they could afford the luxury of full duplex modems using two different frequency pairs for the two directions of transmission. This introduced the complexity that a modem had to know whether it was originating or answering a call to know which pair of frequencies to use for which purpose. Even after Bell began supplying modems for connection of customer-provided data equpment (just before Carterfone) these modems could function in either originating or answering roles. After Carterfone the suppliers of modems for computer time sharing could take advantage of the fact that the terminal always originated and the computer always answered; so we got reduced cost originate-only and answer-only modems. It always seemed to me that the TWX section of Bell Labs was controlled by old geezers who had been around since 1930 and couldn't imagine that a TWX machine would ever want to talk to anything except another TWX machine. If you wanted to use the same kind of Teletype machine to talk to a computer, well that was another matter entirely. The modems had separate originate and answer frequency pairs, each binary FSK. This permitted two options for which frequency pair would be originate and which would be answer, and four possiblities (two for each pair) of which frequency would be mark and which would be space. Thus it was possible by wiring options to set modems up for as many as eight mutually-incompatible services, all using the same voice switched network without any restrictions on area codes and numbers. I remember hearing about TWX, and TWX-prime, and WADS (wide area data service) and WADS-prime, all of which were to use the same modems and switched network without any of these being able to communicate outside its own service. I guess they had in mind different tariffs for TWX machines talking to TWX machines versus terminals talking to computers, versus some other things. Practically all of this was swept away by Carterfone. ////////////////////////////////////////////////////////////////////////////// Newsgroups: comp.dcom.telecom Path: cs.utk.edu!ornl!sunova!linac!uwm.edu!cs.utexas.edu!qt.cs.utexas.edu !yale.edu!newsserver.jvnc.net!howland.reston.ans.net!agate!telecom-request Message-ID: Organization: California Polytechnic State University, San Luis Obispo Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 13, Issue 151, Message 13 of 14 Lines: 59 Date: Wed, 03 Mar 1993 20:00:48 GMT From: hhallika@tuba.calpoly.edu (Harold Hallikainen) Subject: Re: A Little More TWX History Thanks for the interesting history of Teletypewriters! Back in high school I used a model 15 with model 14 tape "typing reperf" and "transmitter distributor" on amateur radio. A friend and I also set up a local teletype network. We ran about a mile and a half of single conductor wire through the trees of the neigborhood. We then fed this wire against ground, running a 60 mA current loop. We made a motor control circuit for each end. When I wanted to leave a message on his machine, I'd supply loop current, which would start both motors. To shut down, I'd drop my loop power supply which would cause both machines to "run open" for a while, 'til a capacitor across a current sense relay discharged, shutting down the AC to the motor. I also remember the very complicated wiring inside the model 15. There was a huge wiring harness that seemed to allow for infinite options. I finally ripped it all out and brought out six wires. Two for the keyboard, two for the "selector magnets" (series for holding magnets at 60 mA, parallel for pulling magnets at 60 mA, or series for holding magnets at 20 mA), and two for AC power to the motor. The previous article spoke of various codes used on Teletypes. I recall seeing machines that LOOKED like model 15s, but used a six level code. These were used by press wire services. The sixth bit allowed for upper and lower case. At my college newspaper, they had one of these printers and a tape punch running all the time. When the editor found an article of interest, he/she would go searching through the punched tape looking for the article. Articles were identified by a number that was punched to be readable in the holes on the tape (and garbage on the printer). This tape was then sent to mechanical Linotype machine where the article was cast in lead. They'd then pull a proof from the lead type, put it in the paste-up for the page. Then they'd photograph the page, make offset plates and print the paper. Watching that Lintotype cast the type to be used just once was pretty amazing! The previous article also mentioned the use of model 15s in radio and TV station wire service use in the 1950s. Here in SLO Town, they were used through the mid 1970s. These were eventually replaced with Extel dot matrix printers, the first dot matrix printer I ever saw. Finally, I still have a model 33 with tape punch, reader and internal Bell 103 modem sitting back in a corner here. When I got it, I was thinking of taking info out of our old CP/M PC board CAD system and generating drill tapes for the PC house. The machine is still sitting in the corner. We now don't even plot our boards. We just take a disk with the Gerber photoplot file and drill file across town to the PC house. We give them a disk and back come PC boards. Pretty neat! It's amazing to see the changes I've seen in the electronics industry ... but then, I'm getting older ... Harold Hallikainen ap621@Cleveland.Freenet.edu Hallikainen & Friends, Inc. hhallika@oboe.calpoly.edu 141 Suburban Road, Bldg E4 phone 805 541 0200 fax 544 6715 San Luis Obispo, CA 93401-7590 telex 4932775 HFI UI ////////////////////////////////////////////////////////////////////////////// Newsgroups: comp.dcom.telecom Path: cs.utk.edu!darwin.sura.net!zaphod.mps.ohio-state.edu !magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!agate!telecom-request Message-ID: Organization: TELECOM Digest Sender: telecom@eecs.nwu.edu Approved: telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 13, Issue 300, Message 1 of 10 Lines: 160 Date: 3 May 1993 10:24:18 GMT From: Jonathan_Welch Subject: History of Mark and Space Pat, I thought the following article might be worth reposting in TELECOM Digest. The original message was posted into a notes conference on a vax DECUS members may subscribe to. Once a month tidbits from various notes conferences are reposted to the outside world. Jonathan Welch VAX Systems Manager Umass/Amherst JHWELCH@ecs.umass.edu ----------- DECUServe Journal, May, 1993 Beginning at page 15 (09/22/90 Harvey: Mark and Space) "Mark" and "space" are curious terms to find in a hardware topic discussing data communication. They seem more appropriate for the Windows conference. But they are truly electrical communication terminology and have many related forms, such as "steady mark", "continuous spacing" and a seemingly unrelated term: "running open". I thought their origin might be of interest and along the way, we'll discover where that curious "break" key came from that many of us have on our keyboards and these days often use to get the attention of the terminal server. These terms are very old and originated with an early graphical device. People never think of the telegraph as graphical communication, but that's the way it was originally conceived. Our impression of the telegraph comes largely from movie stories of times a century ago, when telegraph operators listened to the strange ticks, tocks and rattles from the telegraph sounder and converted them into urgent messages that pushed the plot forward. Morse didn't invent it that way. His original device was an electromagnet that pulled a pen (possibly a quill) against a moving strip of paper. When current flowed through the electromagnet, the pen touched the moving paper and made a mark. When the current was off, a spring retracted the pen and there was a space on the paper. Short marks were called dots. Long marks were called dashes. Now this explanation is so simple and pat, it just has to be largely legend and over-simplification. There were many different schemes, such as keeping the pen in contact with the paper and moving it sideways by the electromagnet. But the mark/space concept seems to have stuck, because it appears in very early communication literature. This graphical device was actually used in production communi- cation for a while. Some of the operators of the machines found that they could recognize the "call letters" of their telegraph office when the electromagnet and pen started tapping out a message on the strip of paper. If the message was for another office, they didn't need to get up to see if the message was for them. Soon, they were able to just write the message down on the telegraph form as it came in without needing to "read" the tape. When the operators were able to fully "read" Morse code with their ears, they could stop putting ink in the pen. The telegraph sounder was born. You couldn't see the marks and the spaces between them anymore, but they were still there in the minds of the engineers designing telegraph systems. For good electrical engineering reasons, telegraph offices were wired in series. At one end of the railroad (for example) there was a powerful battery with one pole connected to a rail and the other connected to a wire that ran on posts for the length of the railway, where it was also connected to the rail. This constituted a simple series circuit with the battery current flowing through the wire, into the rail at the far end, and back through the rail to the battery. At each telegraph office along the line, the wire was cut, brought into the office, sent through the coil of the electromagnet of the sounder, then through the telegraph key, then back up to the pole and on down the line to the next office. But you may have noticed a problem. The telegraph key is normally an open circuit. When the operator pressed down on the key, the circuit was closed and the current flowed. How, then, did the current flow when everything was hooked in series and all those keys were open circuits? If you've ever looked closely at a real telegraph key, you may have noticedthat it has a knife switch build into it, and that switch is arranged to short the contacts of the key. When the operator was not actually sending a message, he or she (many early telegraph operators were women) would close the knife switch so that the key contacts were shorted and the whole series circuit was unbroken. Thus the normal idle telegraph line was in a "steady mark" condition - a current flowed through all the sounders which if the pen was still there would have caused a mark to be made on the moving strip of paper. The knife switch on each telegraph key was perhaps the first "push to talk" button. The operator had to "open" the knife and break the circuit so the key could turn the current on and off and send a message. Not surprisingly, this knife was called the break switch. When an operator opened the knife the current stopped flowing in all the sounder electromagnets and they went tock. Everyone up and down the line knew someone was about to start sending a message. The break switch alerted them. When the Indians cut the telegraph wire, the circuit was open and all the sounders went tock. "Open" meant trouble. The graphical device didn't disappear, however. The interest in having the message automatically recorded on paper that could be read without having to learn the arcane art of "reading" Morse code by ear remained. The inventors worked to improve on the simple marks separated by spaces and actually make letters and figures appear. One early attempt was the telautograph. It attempted to servo the up/down and sideways movements of a pen being used to write a message in longhand to a remote pen reproducing the motion and hence re-creating the longhand. It worked well for very short distances but they didn't have the technology to send the control signals useful distances. There were other schemes using many wires. Expensive. The big winner was the stock ticker. It was the ancestor of all the various asynchronous communication gadgets we have today. It was a triumph of mechanical ingenuity that enabled an ordinary telegraph wire (and there were many) to be converted to actually print a message in letters and figures on that moving strip of paper. You didn't need an expensive telegraph operator hanging around to "read" Morse and you didn't have to puzzle out the strange patterns of marks and spaces. But the communication technology was telegraph and the marks and spaces were still there in the minds of the engineers. The stock ticker used the same series circuit technology of the telegraph. The wire ran from the floor of the exchange to the nearest broker's office, through an electromagnet in the ticker machine, and then on to the next office. And yes, if the Indians (or a cleaning lady) broke the wire anywhere, all the tickers went dead. Dead? No, they went crazy. The continuous telegraph current when there were no stock trades being reported kept the ticker mechanisms idle. Steady mark. Good. The start of a trade message was a break in the circuit (start pulse) which caused the ticker mechanism to start spinning. The following sequence of marks and spaces caused the mechanism to select a particular character on its wheel and a hammer struck the paper strip against it. When the circuit was broken by the cleaning lady, it was in a "continuous space" condition, causing all the ticker machines to spin their clockwork, "running open" until someone fixed the break. These terms stayed with communication technology to the first minicomputers. The venerable ASR 33 Teletype, one of the foundation stones of the minicomputer industry, used telegraph series current loop technology, marks and spaces, and "ran open" when you disconnected it from the PDP-5. Well, if you got this far, you're probably wanting to know about where your break key came from if you haven't figured it out already. Yep, it's that knife switch on the side of the telegraph key. You didn't know you're a telegrapher, did you? [Moderator's Note: Thank you for passing along a fascinating story. PAT] ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.folklore.computers,comp.terminals,comp.terminals.tty5620 Path: cs.utk.edu!lambda.msfc.nasa.gov!sol.ctr.columbia.edu !howland.reston.ans.net!europa.eng.gtefsd.com!uunet!ftpbox!mothost !mdisea!uw-coco!quick!amc-gw!dsinet!jaws!daveb Message-ID: <2392@dsinet> References: Sender: root@dsinet Organization: Digital Systems International, Redmond WA Lines: 66 X-Newsreader: Tin 1.1 PL5 Date: 16 Sep 1993 15:15:16 GMT From: daveb@jaws (David Breneman) Subject: Re: ASR33 info needed Steve Willoughby (steve@aardvark.rain.com) wrote: : : I have a pair of old ASR33 teletypes I'd like to get hooked up to my : computer system, but they don't appear to be using the kind of : interface I need. The teletypes were once used at Western Union, : and have something called a "polar adaptor" built in. I'm not sure : what a "polar" interface is or how it relates to EIA RS232 or 20mA : current loop. Maybe polar is something Western Union did on their : equipment, or maybe it's more common with other ASR33's? I'm a little rusty, but here goes... It's the *standard local* interface for teletypes. The signal is modulated by reversing the phase (I believe) of the current that connects the teletypes; that's where the "bipolar" comes from. That current is sent to the distributor (just like a car ignition, but in reverse :-) ) which breaks it into individual bits, the current from which moves the bars under the keyboard that determine which character will either be typed on the page or punched on the tape. It's the Stop Bit, of RS232 fame, that keeps the distributors in the sending and receiving teletypes in sync. Teletypes that were used in dialup applications had a big 110-baud modem in the base (same tones as 300 baud) and can be connected to a computer by a similar modem on the computer end. As I recall, if the machine you're calling has a 300-baud modem running a 110-baud getty, you can log in (it's been a few years since I've done this, but I *have* done it). As far as *directly* wiring a teletype to a computer a la RS232 or 20mA, you're going to need some kind of conversion box for that, too. : Anyway, I have a set of schematics to the terminals and don't mind : poking around at them to get them to work, but I don't know enough : about this older technology. The interface cable leading out of the : terminal (from the polar adapter) has a ground, send, and receive wire : rather than the four wires I'd expect with 20mA. Yes. And if you try to connect it to anything like a modem or RS232 port, you'll fry it. I think it's about 60 volts going through there (enough current to unlatch the distributor clutch solenoid at the start of each byte)! We're talking industrial data terminal equipment here! :-) : Anyone know how to modify such a machine to work with 20mA or RS232? : Anyone even know what this "polar" interface is or how it works? I don't. I've got two ASR33's with the modem base and I've used one of them to log into a 3B2 a few years ago, but I never tried to re-wire it to do anything else. Check in the ham radio group(s). There's bound to be some RTTY (radio teletype) veterans hanging around in there. Those guys modified ASR33s and the older *big* baudot teletypes to talk over short wave. If anybody would know, they would. (BTW, there was a model of the ???33 which used Baudot 6-bit 66 baud like the older teletypes. Those won't work as a data terminal.) You're best bet might be to find another 33 which is mechanically dead but has a good modem, make one good one and log in that way. I've got two ARS33 manuals kicking around - if there's more info you need I can photocopy the relevant section(s). Drop me a line if I can help. -- David Breneman Email: daveb@jaws.engineering.dgtl.com System Administrator, Voice: 206 881-7544 Fax: 206 556-8033 Software Engineering Services Digital Systems International, Inc. Redmond, Washington, U. S. o' A. ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.folklore.computers,comp.terminals,comp.terminals.tty5620 Path: cs.utk.edu!avdms8.msfc.nasa.gov!sol.ctr.columbia.edu!usc!elroy.jpl.nasa.gov!nntp-server.caltech.edu!almach.caltech.edu!shoppa Organization: California Institute of Technology Lines: 67 Distribution: world News-Software: VAX/VMS VNEWS 1.41 Message-ID: <16SEP199310402717@almach.caltech.edu> References: NNTP-Posting-Host: almach.caltech.edu Keywords: ASR33 TTY help western union Date: 16 Sep 1993 10:40 PST From: shoppa@almach.caltech.edu (Timothy D. Shoppa x4256) Subject: Re: ASR33 info needed Summary: Need to know how to interface ASR33 to system In article , steve@aardvark.rain.com (Steve Willoughby) writes... > >I have a pair of old ASR33 teletypes I'd like to get hooked up to my >computer system, but they don't appear to be using the kind of >interface I need. The teletypes were once used at Western Union, >and have something called a "polar adaptor" built in. I'm not sure >what a "polar" interface is or how it relates to EIA RS232 or 20mA >current loop. Maybe polar is something Western Union did on their >equipment, or maybe it's more common with other ASR33's? > I had a ASR33 teletype hooked to my S100 system a long, long, time ago. The ASR33 had been used for Telex at a local company before they switched to something a little more modern. It also had this "polar adaptor" on it when I got it. Luckily, I also got the manual set for the ASR33 with it, and it was clear enough how to convert back to 20mA current loop. If you don't get any other replies, let me know and I'll hunt down my ASR33 manual set for you (it's 2000 miles away at the moment, so it'll take a while!) If I remember correctly, the idea behind the "polar adaptor" was that if you had a long circuit, possibly with many relays in the circuit to "repeat" the signal, you ran into a problem if the relay was only "on" and "off": most relays take a different amount of time to turn on and off. Thus you can end up with distorted bits getting passed around, as the effective delay for the "rise" part was different than the effective delay for the "fall" part. The polar relay got around this by making things more symmetrical; I don't remember the details, but I believe a current flowing one way meant a mark, and the reverse current meant a space. These currents triggered the beast known as the "polar relay", the innards of which I don't have much knowledge of. You might try looking in an older ARRL (Amateur Radio Relay League) Handbook, from the mid-70's or so. Ham radio operators have for a long time been taking old teletype equipment for use on radioteletype. Usually the equipment was Baudot, not ASCII, but I believe that polar relays could also used in the Baudot equipment as well. The Handbook explained the polar relay concept a little more clearly than I have done. There was also another ARRL publication, "Specialized Communication Techniques", which was supposed to discuss radioteletype equipment in a little more detail than the Handbook. Nearly all public libraries have back editions of the ARRL Handbook. >Anyway, I have a set of schematics to the terminals and don't mind >poking around at them to get them to work, but I don't know enough >about this older technology. The interface cable leading out of the >terminal (from the polar adapter) has a ground, send, and receive wire >rather than the four wires I'd expect with 20mA. I believe that if you hook a scope up to the "send" line and type some characters on the keyboard, you'll see positive-negative voltage swings corresponding to marks and spaces. I can't remember exactly what the swings are, though; probably of the order 50-60 volts on an open circuit. Hooking the "send" line to the "receive" line will probably give you local loopback, if you want to play around. > >Anyone know how to modify such a machine to work with 20mA or RS232? I believe you can get inside and get to the 20mA loop part quite easily. (Or were ASR33's 60mA loop? No, I think 60mA was only on the older Baudot equipment, but I could be wrong.) At least that was the case on mine; but on mine it was pretty clear the the polar relay was not part of the original equipment. Tim (KA0BTD) (shoppa@almach.caltech.edu) ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.folklore.computers,comp.terminals,comp.terminals.tty5620 Path: cs.utk.edu!darwin.sura.net!howland.reston.ans.net!usenet.ins.cwru.edu!ncoast!dchou Organization: North Coast Public Access *NIX, Cleveland, OH Message-ID: Keywords: ASR33 TTY help western union References: <16SEP199310402717@almach.caltech.edu> Lines: 21 Date: Fri, 17 Sep 1993 07:31:46 GMT From: dchou@NCoast.ORG (David Chou) Subject: Re: ASR33 info needed Back in 1976 or so, I actually bought an ASR-33 (brand new) from Teletype Corporation and converted it to RS-232 use. As the previous posters have mentioned, there are a number of configurations. The basic unit consisted of a current loop unit, usually defaulting to 20ma, but I do remember that you could change a jumper to get 60ma current loop. The output of the system is between 60-80 volts off the current loop, so it can do a good job of blowing things on solid state 5 v circuits being used today. It is also possible to wire the circuits to that the tty would source the current or the user could provide an external source. I think that I used the latter option. I remember building a current loop to RS-232 convertor using some 741 op amps and a +/-12 volt supply using junk from Radio Shack (shudder). The ASR-33 sits behind me collecting dust. The manuals provided by TTY are very complete, but are somewhat difficult to decipher. It would take me some time to decipher what I have done, but if anyone needs help and is willing to wait, please ask. Incidentally, I love those mechanical clunkers, but the noise was over- whelming and the speed was underwhelming! Dave ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.folklore.computers,comp.terminals,comp.terminals.tty5620 Path: cs.utk.edu!gatech!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!pipex!warwick!bsmail!siva.bris.ac.uk!ard Message-ID: <15SEP199322222814@siva.bris.ac.uk> News-Software: VAX/VMS VNEWS 1.41 Keywords: ASR33 TTY help western union Sender: usenet@info.bris.ac.uk (Usenet news owner) Nntp-Posting-Host: siva.bris.ac.uk Organization: University of Bristol Physics Department References: Lines: 50 Date: Wed, 15 Sep 1993 21:22:00 GMT From: ard@siva.bris.ac.uk (PDP11 Hacker .....) Subject: Re: ASR33 info needed Summary: Need to know how to interface ASR33 to system In article , steve@aardvark.rain.com (Steve Willoughby) writes... > > I have a pair of old ASR33 teletypes I'd like to get hooked up to my > computer system, but they don't appear to be using the kind of > interface I need. The teletypes were once used at Western Union, > and have something called a "polar adaptor" built in. I'm not sure > what a "polar" interface is or how it relates to EIA RS232 or 20mA > current loop. Maybe polar is something Western Union did on their > equipment, or maybe it's more common with other ASR33's? Can't help that much but it gets a mention in the ASR33 service manual volume 1 (which unfortunately does not contain a schematic). However, it appears that the transmit and receive circuits both use mercury-contact relays that are sensitive to the direction of current flow through the coils (the polar part). The transmit output seems to be the contact set (SPCO) of one of these relays, connected to a +/- 120V supply (but with links to use an external PSU). The receive input is the coil of such a relay, and requires similar voltages. So, it looks like a high-voltage RS232-type interface. > >Anyway, I have a set of schematics to the terminals and don't mind >poking around at them to get them to work, but I don't know enough >about this older technology. The interface cable leading out of the >terminal (from the polar adapter) has a ground, send, and receive wire >rather than the four wires I'd expect with 20mA. It's a voltage interface, so 3 wires, Tx, Rx and common ground. In England (and probably elsewhere), telex systems used an 80V line, which may well be similar. > >Anyone know how to modify such a machine to work with 20mA or RS232? >Anyone even know what this "polar" interface is or how it works? Try digging for the 'private line call control unit' - that was 20mA I think. Otherwise, transmit (from ASR -> computer) should be possible by reducing the PSU voltage on the relay contacts to +/- 12V, and calling it RS232. Receive may need a relay swap, or a bit of hacking to the circuitry to get an RS232 level to switch the existing relay If you blow up your computer, it's not my fault :-) (Note, you'll not blow up the ASR33) > >Thanks, >steve >-- >Steve Willoughby N7PFJ | "Bart, don't use the Touch of Death on your sister!" >steve@Aardvark.Rain.Com | --Marge Simpson > |--------------------------------------------------- -tony ////////////////////////////////////////////////////////////////////////////// Newsgroups: vmsnet.pdp-11,alt.sys.pdp11 Path: cs.utk.edu!gatech!news.mathworks.com!newsfeed.internetmci.com!news.sprintlink.net!in2.uu.net!library.erc.clarkson.edu!rpi!not-for-mail Organization: Rensselaer Polytechnic Institute Lines: 24 Message-ID: <4591f8$19no@alum01.its.rpi.edu> References: NNTP-Posting-Host: alum01.its.rpi.edu Date: 8 Oct 1995 13:23:52 -0400 From: wilsonj@alum01.its.rpi.edu (John Wilson) Subject: Re: Teletype 43 teleprinter (KSR) ribbons In article , Bob Manners wrote: >I wonder if anyone out there knows of a source for ribbons for the KSR >43? I don't know the 43, are these the same little spool ribbons used on other TTYs like the 33? If so, they had them in stock at our local Office Max a couple of weeks ago, I was amazed! I think it was made by Pelican (or is that Pelikan), the model 33 wasn't specifically listed but a few other TTY models were, and scads of other brands, ASR33s supposedly use the same ribbon as the old Underwoods too so you might try a typewriter store if they still exist in your area. It fit perfectly, although it was a little dry. If the 43 takes some weird cartridge thing then never mind, I have no idea what I'm talking about. The LA120 ribbon appears to be the same width, if you really hate yourself you could thread part of one onto your old spools, I don't know what you'd use for the reversing rivets though. Also discovered: soaking an ASR33 type cylinder in a carburetor cleaning bath does a nice job of getting all the gunk out so your O's don't come out as disks... John Wilson ////////////////////////////////////////////////////////////////////////////// Newsgroups: vmsnet.pdp-11,alt.sys.pdp11 Path: cs.utk.edu!news.msfc.nasa.gov!newsfeed.internetmci.com!chi-news.cic.net !uwm.edu!fnnews.fnal.gov!nntp-server.caltech.edu!altair.krl.caltech.edu !shoppa Organization: Kellogg Radiation Lab, Caltech Lines: 25 Message-ID: <45cklb$11f@gap.cco.caltech.edu> References: NNTP-Posting-Host: altair.krl.caltech.edu Date: 10 Oct 1995 02:09:47 GMT From: shoppa@altair.krl.caltech.edu (Tim Shoppa) Subject: Re: Teletype 43 teleprinter (KSR) ribbons In article , Bob Manners wrote: > >I wonder if anyone out there knows of a source for ribbons for the KSR >43? I've had no luck with the local suppliers, Inmac et. al. My Inmac catalog (Summer '95 Vol 1016M) lists model 43 ribbons, minimum order 6, at $7.94 each. Part number H6445. They also have Model 33 ribbons (also available at any five-and-dime as regular typewriter ribbons) at $2.78 each, part number H6143. Their 1-800 number is plastered all over the catalog (1-800-972-3210), but I can't find any trace of a regular number for people out of the states. Inmac no longer appears to carry 8.5" paper rolls (with sprocket holes at approx. 8" spacing), as are used on my model 33's. Interestingly enough, the picture of the Wright-line type storage cabinet (p. 87 in my Inmac catalog) still shows RK05-type cartridges (on a cartridge rack), RP06-type cartridges, and RM03-type cartridges (these are on a shelf). Not too long ago you could buy these cartridges new from Inmac. They're still available from DECdirect, BTW. (Last time I checked, RK05's were about $135 each, RP06's were about $1000 each, and RM03's were $255. RL02's are about $200, I think.) Tim. (shoppa@altair.krl.caltech.edu) ////////////////////////////////////////////////////////////////////////////// Newsgroups: vmsnet.pdp-11,alt.sys.pdp11 Path: cs.utk.edu!nntp.memphis.edu!nntp.msstate.edu!gatech!news.mathworks.com !tank.news.pipex.net!pipex!sunsite.doc.ic.ac.uk!lyra.csx.cam.ac.uk!ard12 Message-ID: <45g7n7$39j@lyra.csx.cam.ac.uk> References: <4591f8$19no@alum01.its.rpi.edu> Organization: University of Cambridge, England NNTP-Posting-Host: tw500.eng.cam.ac.uk Lines: 33 Date: 11 Oct 1995 10:53:27 GMT From: ard12@eng.cam.ac.uk (A.R. Duell) Subject: Re: Teletype 43 teleprinter (KSR) ribbons wilsonj@alum01.its.rpi.edu (John Wilson) writes: >In article , >Bob Manners wrote: >>I wonder if anyone out there knows of a source for ribbons for the KSR >>43? >I don't know the 43, are these the same little spool ribbons used on other >TTYs like the 33? If so, they had them in stock at our local Office Max Alas the KSR43 takes a very odd cartridge. It's held down by a magnetic catch on the right side of the printer chassis, and the ribbon is threaded round a set of one-way rollers on the chassis and carriage that advance the ribbon when the carriage moves. >a couple of weeks ago, I was amazed! I think it was made by Pelican (or >is that Pelikan), the model 33 wasn't specifically listed but a few other >TTY models were, and scads of other brands, ASR33s supposedly use the same I will look out for that. I still run an ASR33. And, of course the same ribbon fits the Microline 80 and some old commodore printers. >Also discovered: soaking an ASR33 type cylinder in a carburetor cleaning >bath does a nice job of getting all the gunk out so your O's don't come out >as disks... I'll try that as well. Cleaning the type cylinder is not that trivial on any machine, but it's worth doing... >John Wilson -tony ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.sys.pdp11,vmsnet.pdp-11 Path: cs.utk.edu!gatech!news.mathworks.com!uunet!in1.uu.net!library.erc.clarkson.edu!rpi!not-for-mail Organization: Rensselaer Polytechnic Institute Lines: 13 Message-ID: <463md6$1cd2@alum01.its.rpi.edu> NNTP-Posting-Host: alum01.its.rpi.edu Date: 18 Oct 1995 16:00:38 -0400 From: wilsonj@alum01.its.rpi.edu (John Wilson) Subject: TTY ribbons It's amazing how fast articles expire on this server... Well sorry to bug the newsgroup with this but a short while ago someone was looking for ribbons for some TTY model I'm not familiar with, I think it was model 43. If so, there's an entry in the Global catalog for "Teletype 43 W/Clip", whatever that means. Part # is KC2316, price is $6.75. They also list the model 14 (presumably they're referring to the 14TR since the other 14s don't type anything!) but not the myriad of other TTYs that take the same ribbon, so they may be insane. Anyway their phone # is 1-800-8GLOBAL, they don't mention whether they accept international orders but their NE warehouse is +1-516-625-6200, give it a shot. If it wasn't a model 43 or the Clip is important, then never mind, as I say the article has evaporated here. John Wilson ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.sys.pdp8 Path: cs.utk.edu!stc06.ctd.ornl.gov!fnnews.fnal.gov!nntp-server.caltech.edu !nntp1.jpl.nasa.gov!news.spies.com!genmagic!sgigate.sgi.com!nntp.coast.net !zombie.ncsc.mil!news.mathworks.com!newsfeed.internetmci.com !usenet.eel.ufl.edu!arclight.uoregon.edu!dispatch.news.demon.net!demon !sunsite.doc.ic.ac.uk!lyra.csx.cam.ac.uk!ard12 From: ard12@eng.cam.ac.uk (A.R. Duell) Subject: Re: PDP-8/e and 33s Date: 3 May 1996 09:48:14 GMT Organization: University of Cambridge, England Lines: 37 Message-ID: <4mckou$7ar@lyra.csx.cam.ac.uk> References: <4m7gmc$8dn@tlaltec.tezcat.com> <8BFD080.0BBF000076.uuout@compudata.com> david.razler@compudata.com (DAVID RAZLER) writes: > > Technically (by Teletype maintenance manuals) the "upper cylinder" is a > dashpot, a mechanism that dampens the inertia of the print head after a > carriage return by trapping air against the cylinder on the print head > and the receiver attached to the main portion of the frame. I know that dashpot well (having had to set up the air hole adjustment on it), but I've never heard it called the 'upper cylinder' I will have to check in the partsbook... > Teletype Corp. used this technology at least from the 10-series machines > through the 34/5 series. > The exact amount of air to trap to get each line to line up with those > above and below is determined by either long experience or a technology > so advanced that it is indistinguishable from magic. There is an adjustment on the side that affects the time it takes for the air to escape, and hence the carriage return time. You have to set it so that the carriage returns correctly in one character time, but doesn't bounce. I am told that the correct setting depends on the altitude that the machine is installed at :-) > I've never tried improving the seal with STP, though I have seen use of > Vaseline on 'newer' Teletypes which used a plastic piston head. (I just The older '33s seem to have a metal piston with a rubber insert in it (which seems to be a damper, rather than a seal.)> -- -tony ard12@eng.cam.ac.uk The gates in my computer are AND,OR and NOT, not Bill ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.folklore.computers Message-ID: <5humn0$ped@lyra.csx.cam.ac.uk> Date: 2 Apr 1997 22:30:56 GMT From: "A.R. Duell" Subject: Re: Modems invented? Robert Billing writes: >In article <5hctit$elp@netaxs.com> hancock4@bbs.cpcn.com "Lisa or Jeff" writes: >> Any details about that early service would be appreciated. Thanks. > You may also be interested in the box which was supplied by Post >Office Telephones (now BT) for early dial-up connections in the late >60s and early 70s. The box was about the size of a modern PC desktop >case, and IIRC provided full duplex at 110 baud for a Teletype ASR33. You may be thinking of a Modem 2B. That's a brown and grey metal box about 15" square and 7" high, containing 4 plug-in modules (PSU, modulator, demodulator, control). It's all discrete transistors, of course. I beleive the demodulator mixed the incoming carrier with a local oscillator, took the sum frequency, filtered it (with a chain of LC filters in a tobacco-tin sized box), and the used a standard FM detector on the output. Amazingly it works. The 2B is good to 300 baud, AFAIK, and mine uses a standard RS232 interface, correctly implemented. > Dialling was by an ordinary rotary dial phone, and a button on the >phone switched the line over to the modem when you heard carrier. The most amazing GPO modem I ever saw is the 13A. This is a complete 300 baud modem in a 1" high plinth that's screwed to the bottom of a modified type 746 'phone. There's a 'voice' and 'data' button on the 'phone, and a 4 core cable coming out of the pinth ending in a DB25-S RS232 connector (TxD, RxD, SG, CD are the signals, I think). It uses some metal-can IC's, and a lot of pot-core inductors. -- -tony ard12@eng.cam.ac.uk The gates in my computer are AND,OR and NOT, not Bill ////////////////////////////////////////////////////////////////////////////// Message-ID: <5i1aop$bpj@tor-nn1-hb0.netcom.ca> Date: Thu, 03 Apr 1997 22:20:40 GMT From: John Savard Newsgroups: alt.folklore.computers Subject: Re: origins of '\' (backslash) on keyboards? snorwood@nyx10.cs.du.edu (Scott Norwood) wrote: >I remember reading with interest the thread on the origins of the '\' >as a directory separator for M$-DOS (as opposed to the '/' used in UNIX). >Now, here's another question: at what point did the backslash key >become standard for computer keyboards? Well, back in 1964, when the original ASR-33 Teletype was produced-- when ASCII was invented, in other words--the backslash was part of the character set. Back then, the caret was instead an up arrow (which it should have remained, being useful as an exponentiation operator); the underscore was an arrow pointing left; and there were no lowercase characters; ` { | } and ~ did not exist yet. However, in addition to DEL, the last few characters before it were controls as well: ACK, ESC, and ALT MODE then are now printing characters, and a different control character is used for ESC. The last 8 of the first 32 characters did not have their present meanings; they were just S0 through S7. John Savard ////////////////////////////////////////////////////////////////////////////// Newsgroups: alt.folklore.computers Date: Thu, 03 Apr 1997 22:23:33 GMT Message-ID: <5i1au5$bpj@tor-nn1-hb0.netcom.ca> From: John Savard Subject: Re: origins of '\' (backslash) on keyboards? In <3340bb0f.65034735@news.sci.fi>, keinanen@sci.fi (Paul Keindnen) wrote: > > While strictly speaking ASCII is a purely US standard, many national > 7-bit character sets exist in the rest of the world, which are almost > identical to the ASCII character set, but a few character positions > are reserved for national variations. Yes, and these character sets belong to International Telegraph Alphabet No. 5, which is the international version of ASCII; so there is a worldwide standard based on ASCII. John Savard ////////////////////////////////////////////////////////////////////////////// Newsgroups: bit.listserv.ibm-main, alt.folklore.computers Message-ID: References: <004f01c387d7$f60e0c20$e535a5d1@FJPx> Organization: Wheeler&Wheeler Date: Wed, 01 Oct 2003 15:34:25 GMT From: Anne & Lynn Wheeler Subject: Re: model 91/CRJE and IKJLEW PaulW@ENET.COM (Paul Wendt) writes: > > Ah, CRJE...there's a text editor out of the past! sometime late '68 (undergraduate at university), i had hacked HASP ... removed the 2780 support and misc. other stuff (to pick up size in the program) and substituted 2741 and TTY support along with an editor that implemented the CMS editor syntax for an early kind of CRJE (it wasn't the actual CMS editor since it was quite non-reentrant, but the same syntax rewritten from scratch). I had previously added TTY support to CP/67 ... and had tried to implement dynamic terminal recognition (between TTY and 2741). After it seemed to be working, the IBM CE got around to telling me that they had taken short-cut on the 2702 and hardwired the oscilator to individual ports. While it was possible to use the 2702 SAD command to dynamically change the association of the line scanner type to each individual line ... it wasn't actually possible to change the baud rate on a line (since it was hard wired). This in turn kicked off the university effort where four of us got blamed for originating the PCM controller business: http://www.garlic.com/~lynn/subtopic.html#360pcm starting with an Interdata/3, reverse engineering the 360 channel interface, building our own channel interface for the Interdata/3 and writing 2702 emulator for the Interdata/3. All in order to get dynamic terminal type (and baud rate) identification. -- Anne & Lynn Wheeler | http://www.garlic.com/~lynn/ Internet trivia 20th anv http://www.garlic.com/~lynn/rfcietff.htm ////////////////////////////////////////////////////////////////////////////// Newsgroups: comp.terminals NNTP-Posting-Host: panix5.panix.com NNTP-Posting-Date: Wed, 1 Oct 2003 02:34:41 +0000 (UTC) References: Message-ID: Organization: Jeff's House of Electronic Parts Date: 30 Sep 2003 22:34:48 -0400 From: Jeff Jonas Subject: Re: 20mA Current loop TTYs >> I am the proud restorer of a PDP-7 computer, which utilized a >> 20mA current loop KSR33 [as its console]. >> >> The KSR33 is dead. I'm working on fixing it, but I'd much much rather >> be working on the logic circuits inside this DECbeauty. There are RS232 <-> current loop adapters. Build your own or buy pre-built: http://www.pccompci.com/converter/converter5.html http://www.lanode.com/tier2/cloop.htm http://www.decisioncards.com/adapt/current_loop.html //////////////////////////////////////////////////////////////////////////////