wa371@sdcc12.ucsd.EDU (Bernd) (01/08/87)
Is it possible somehow to use the typical 300 or 1200 baud modem to link up with a TDD (telecommunications device for the deaf)?? TDD is a slow speed teletypewriter or sorts. I just met a friend who is deaf, and we have to communicate through a relay service, where a third party (free of charge) reads for one and types for the other while on the telephone. It is kind of backward, to put it mildly. I tried it at various baud settings of my terminal through a PASSWORD modem. But although my modem said "connect", I got only garbage. Cheers, Bernd <Bernard> UUCP: ...!sdcsvax!sdcc12!wa371, Internet: wa371%sdcc12@sdcsvax.ucsd.edu FAX: (619)569-8296, VOICE:(619)569-6800/270-5754
klr@hadron.UUCP (Kurt L. Reisler) (01/08/87)
In article <763@sdcc12.ucsd.EDU> wa371@sdcc12.ucsd.EDU (Bernd) writes: >Is it possible somehow to use the typical 300 or 1200 baud modem to >link up with a TDD (telecommunications device for the deaf)?? >TDD is a slow speed teletypewriter or sorts. I just met a friend >who is deaf, and we have to communicate through a relay service, >where a third party (free of charge) reads for one and types for the >other while on the telephone. It is kind of backward, to put it >mildly. >I tried it at various baud settings of my terminal through a PASSWORD >modem. But although my modem said "connect", I got only garbage. >Cheers, >Bernd <Bernard> >UUCP: ...!sdcsvax!sdcc12!wa371, Internet: wa371%sdcc12@sdcsvax.ucsd.edu >FAX: (619)569-8296, VOICE:(619)569-6800/270-5754 I recently had a user upload a package called TDD54.ARC, which is a TDD emulator for a Tandy Color computer and the IBM PFJr. The ARChive also includes very well written documentation AND source code for both versions of the package. It might be a useful starting point for someone to write a C version of the program that might be distributed both through this forum as well as the BBS communities. TDD54.ARC is available for downloading (XMODEM, MODEM7, KERMIT, TELELINK) to ALL callers from FidoNet 109/483 (The Pot of Gold) at 703-359-6549. Let me know if it is helpful Kurt Reisler ============================================================================ UNISIG Chairman, DECUS US Chapter | Hadron, Inc. ..{seismo|sundc|rlgvax|dtix|decuac}!hadron!klr | 9990 Lee Highway Sysop, Fido 109/74 The Bear's Den (703) 671-0598 | Suite 481 Sysop, Fido 109/483 Wash-A-RUG (703) 359-6549 | Fairfax, VA 22030 ============================================================================
kent@decwrl.DEC.COM (Christopher A. Kent) (01/08/87)
Fortunately or unfortunately, TDDs have been around a long time. Longer than ASCII, in fact. Thus, they don't speak ASCII. They use a 5 or 6 bit code called Baudot (it's been too long since I thought about this to recall the details). So while the modems might be compatible, the "terminals" aren't. At one time, I played with the design of a box that would translate. It's really quite straightforward to do; a look-up table and a small finite state machine (implemented in a micro, of course) connected to two UARTs. There might even be a market to do this commercially, though most TDDs have a fairly limited display (typically one line of 30-50 characters) so they aren't much good for general purpose terminals. chris -- Chris Kent Western Research Laboratory Digital Equipment Corporation kent@decwrl.dec.com decwrl!kent (415) 853-6639
edm@tikal.UUCP (Ed Morin) (01/09/87)
I believe the terminals/modems that deaf folks use talk Baudot (sp?) instead of ASCII. It's a completely different data standard...
rph@rocksanne.UUCP (Bob Herloski) (01/09/87)
In article <763@sdcc12.ucsd.EDU> wa371@sdcc12.ucsd.EDU (Bernd) writes: >Is it possible somehow to use the typical 300 or 1200 baud modem to >link up with a TDD (telecommunications device for the deaf)?? >TDD is a slow speed teletypewriter or sorts. I just met a friend >who is deaf, and we have to communicate through a relay service, >where a third party (free of charge) reads for one and types for the >other while on the telephone. It is kind of backward, to put it >mildly. >I tried it at various baud settings of my terminal through a PASSWORD >modem. But although my modem said "connect", I got only garbage. This is how I understand the TDD protocol: (1) It is a 5-bit Baudot coding (2) Most (older) TDD's use FSK at 45.45 (or is it 55?) baud. (3) Since it is a half-duplex protocol, there is no difference between sending/ receiving/originating/answering frequencies: I believe that the mark and space frequencies are 1400 Hz and 1800 Hz (or it might be 1800 and 1400). This is unlike the standard Bell 103 protocol in your 300 baud modem. Several years ago I built a modem to act as a TDD interface for my C64; I'm sorry if I don't have the details exactly correct; my notes are at home. There are some newer TDD's that implement both the old style Baudot coding AND ASCII at 300 baud (switch-selectable). I hope this helps. (Comments and/or corrections from the net are welcome!) -- Bob Herloski ...!seismo!rochester!rocksanne!rph <<< No fancy signature >>>
ralphw@ius2.cs.cmu.edu (Ralph Hyre) (01/09/87)
The Novation Apple-Cat is the only modem I know of that gives you TDD capability along with other protocols (Bell 103/202/212). Unfortunately, it's an internal modem that works on an Apple ][ bus. -- - Ralph W. Hyre, Jr. Internet: ralphw@ius2.cs.cmu.edu Phone: (412) 268-2847 [CMU-BUGS], 268-3275 Amateur Radio: KA3PLY temporary KT (c/o W3VC, CMU Radio Club, Pittsburgh, PA)
paul@imsvax.UUCP (Paul Knight) (01/09/87)
The company I work for, Integrated Microcomputer Systems, Inc., sells
an IBM-PC compatible board which supports TDD communications.
At the risk of sounding like a commercial and being Osterized :-) I'll
provide the following info:
- Supports all new and/or old TDD/TTY communication, both domestic
(45.5 baud) and international (50 baud).
- Also functions as a 300 baud ASCII modem.
- Phone jack plug.
- Automatic incoming call detection/identification, switching to TDD
or ASCII as appropriate.
Software is also supplied, which provides a fairly complete desktop
environment, supporting automatic answering, delivery of pre-recorded
messages, capture of incoming text, along with calendar, memo pad,
phone directory with autodial, etc.
IMS also sells complete systems, with 640K, twin floppies, monitor, and all
the above for around $1800. I'm not sure of pricing for the board alone.
For more info, mail (please don't post to net!!) to me, or better, write to
Dillip Emmanuel
Integrated Microcomputer Systems
2 Research Place
Rockville, MD 20850
or call him: (301)948-4790, x-350 or with TDD, call (301)869-2950.
Dillip doesn't have a net.address now (he's a pure PC man), but if there's
sufficient mail to me, I'll get him on the net.
Paul Knight -- elsie!imsvax!paul; paul@imsvax.UUCP
--
Paul Knight
God created man in his own image.
Man, being a grateful creature, returned the favor.wcs@ho95e.UUCP (#Bill.Stewart) (01/12/87)
There are some commercial Baudot-to-ASCII converters out there which would probably work. Black Box Corp. in Pittsburgh makes one. Or you can scrounge around for a Model 28 Teletype, the ancestor of the TDD :-) -- # Bill Stewart, AT&T Bell Labs 2G-202, Holmdel NJ 1-201-949-0705 ihnp4!ho95c!wcs
jc@piaget.UUCP (John Cornelius) (01/14/87)
In article <594@tikal.UUCP> edm@tikal.UUCP (Ed Morin) writes: > >I believe the terminals/modems that deaf folks use talk Baudot (sp?) instead >of ASCII. It's a completely different data standard... The _modems_ are the Bell 103 style and are compatible with the 300 baud signalling of 300/1200/2400 baud modems. The character set is 5 bit baudot which uses the SI/SO characters to get 64 characters into the character set. Baudot isn't very much like ASCII and it's upper case only as I recall. Some smart modems won't accept or send data at 50 Baud because they look at the serial bit stream (+++) for command information. -- John Cornelius (...!sdcsvax!piaget!jc)
speaker@ttidca.UUCP (Kenneth Speaker) (01/15/87)
In article <763@sdcc12.ucsd.EDU> wa371@sdcc12.ucsd.EDU (Bernd) writes: >Is it possible somehow to use the typical 300 or 1200 baud modem to >link up with a TDD (telecommunications device for the deaf)?? >TDD is a slow speed teletypewriter or sorts. ... >I tried it at various baud settings of my terminal through a PASSWORD >modem. But although my modem said "connect", I got only garbage. I believe that TDD's use 5-level BAUDOT code at 75 baud. If this is correct, you need a translator, unless you have a PC-like device that can fake it. Ok course, then your intellegent modem might misunderstand certain combinations of 5-bit characters... Yes, aren't 75 baud, 37.5 baud and even 18.75 baud standards of yesteryear wonderful? --Kne
wtm@bunker.UUCP (01/15/87)
In article <763@sdcc12.ucsd.EDU> wa371@sdcc12.ucsd.EDU (Bernd) writes: >Is it possible somehow to use the typical 300 or 1200 baud modem to >link up with a TDD (telecommunications device for the deaf)?? The question of TDD communications came up back in September in a different news group. I'm taking the liberty of reprinting Dick Barth's article since he does not get the news. Dick operates the HEX BBS (Handicapped Educational Exchange), accessible to both 300 baud ASCII callers and TDD/TTY callers. The HEX phone number is (301) 593-7033. As mentioned in an earlier article on this subject, the public domain software mentioned here is available on many BBS's. Hope this helps. Bill McGarry (Moderator of the Handicap Digest/News) Bunker Ramo, Shelton, CT (203) 337-1518 PATH: {philabs, decvax, ittatc}!bunker!wtm *********************************************************************** From: BARTH@AI.AI.MIT.EDU Newsgroups: net.micro Subject: TDD/TTY Communications Date: 26 Sep 86 10:37:35 GMT Sender: news@brl-smoke.ARPA In a net msg, Scott Phillips (AWD) <scottp@AMSAA.arpa> writes: Quote I have a friend who has had severe hearing loss. She has started a local chapter of SHHH (Self Help for the Hard of Hearing). With her hearing problems coordinating activities is a bear. She has a Sanyo MB 550 PC and was told all she needed was a MODEM and she could use the TDD/TTY communications that many hearing impaired have. She got a Hayes 1200 MODEM and now has been looking for software. The companies she has been able to contact want to sell their hardware (their own MODEM, etc.) and software. Is their anyone familiar with these devices and communications software that can advise what the best approach is? Is there software available for a standard MODEM? .... A TTY, also known as a TDD, is not compatible with a Bell-103, a -212, or any other kind of ASCII modem. A TTY is compatible only with another TTY. Anybody who tries to tell you a Hayes only needs software to talk to a TTY is either talking through his hat or, as you suggested, "...want(s) to sell their hardware (their own MODEM, etc." A TDD modem uses Frequency Shift Keying, like a 103, but the tones are different. Mark freq is 1400 Hz, Space is 1800 Hz. Same freqs are used in each direction. The TDD is a half-duplex device and only one end can type at a time. The TDD also uses Baudot code, not ASCII. Any communications software that wants to talk TDD had better know how to do code conversion. Baud rate for Baudot is 45.45 baud, or 60 wpm. There are a very few TTYs (e.g. Ultratech Superphone, Krown Porta- Printer Plus) that handle both normal TTY as described above, and ASCII. This ASCII uses Bell-103 tones and isusually 110 baud, although 300 is sometimes provided. There are, to my knowledge, three commercial TTY modems on the market. One is the Model CM-4 by Phone-TTY Inc. of Hackensack, NJ. It provides both TTY capability and Bell-103 originate and answer. Its data input is via an RS-232 port, so it is usable with almost any computer. It comes with software for MS-DOS which allows TTY and ASCII commo, and also takes messages over the phone in either mode. Callers may also read messages left for them by the system operator. It is not a full-blown BBS, as callers may not leave messages for each other. A second device by Krown provides its own code conversion, and is thus usable with a dumb terminal. It also provides TTY, and ASCII in 7E1 format only, so is not usable for XMODEM file transfers. A third modem is a plug-in for the IBM-PC bus, provides TTY/ASCII originate and ASCII answer. Comes with software. Source is Integrated Micro- computer Systems of Rockville MD. A TTY modem is a relatively simple device, and you can build one using Exar 2206 and 2211 modem chips from Radio Shack. Signetics MF-10 switched capacitor filters from the same source match well. A VADIC -103 modem card is available through the Amateur Radio R&D Corporation (AMRAD) for $25 or so. It comes with instructions for modifying it to TTY operation. The Handicapped Educational Exchange BBS, which is sponsored by AMRAD and operated by me, uses one of these to provide the ability to answer TTY as well as ASCII calls. HEX is on (301) 593-7033 and provides files with further information on all of this. There is public domain software for the IBM-PC and PCjr, and for the Radio Shack Color Computer, that permits these machines to talk to TTYs without using a modem. The cassette port hardware is used to emulate the modem and a Radio Shack telephone amplifier (modified according to instructions provided) couples the computer to the phone line, legally. This software is available from some BBS systems, the latest version being in an ARC file called TDD54. The file, as I distribute it, contains source, listing and executable for the PC/PCjr, and source for the CoCo. A user's manual is also provided. If the file isn't on your favorite BBS, send me a blank floppy and return postage and I'll load 'er up and return 'er. Address is: Handicapped Educational Exchange 11523 Charlton Drive Silver Spring MD 20902 Further distribution of the above info, and the software, is welcomed. The programs mentioned are by John Spalding of Atlanta, GA.
mikec@tekred.UUCP (01/16/87)
> >I believe the terminals/modems that deaf folks use talk Baudot (sp?) instead > >of ASCII. It's a completely different data standard... > >The _modems_ are the Bell 103 style and are compatible with the >300 baud signalling of 300/1200/2400 baud modems. The character >set is 5 bit baudot which uses the SI/SO characters to get 64 >characters into the character set. Baudot isn't very much like >ASCII and it's upper case only as I recall. Does this mean that you need only a software Baudot/ASCII translation to enable your personal computer to talk with a TTD? <extra text so the mail program won't reject this. :-( > Mike A. Combs | GEnie: mike.combs | MCI: mcombs | tektronix!tekgen!tekred!mikec ^--The "A" is for: "Accidently erased the files". "How much can YOU put in a four line .signature file?" terrorist, contras, drugs, Iran, secret, NSA, CIA <- NSA line-eater food :-( -- Mike A. Combs | GEnie: mike.combs | MCI: mcombs | tektronix!tekgen!tekred!mikec ^--The "A" is for: "Accidently erased the files". "How much can YOU put in a four line .signature file?" terrorist, contras, drugs, Iran, secret, NSA, CIA <- NSA line-eater food :-(
maryr@well.UUCP (01/31/87)
9@ho95e.UUCP> Sender: Reply-To: maryr@well.UUCP (Mary C Rinaldi) Followup-To: Distribution: Russia Organization: Whole Earth Lectronic Link, Sausalito CA Keywords: TDD deaf You mean my $600 Hayes won't communicate with TDD?
maryr@well.UUCP (01/31/87)
9@ho95e.UUCP> Sender: Reply-To: maryr@well.UUCP (Mary C Rinaldi) Followup-To: Distribution: na Organization: Whole Earth Lectronic Link, Sausalito CA Keywords: TDD deaf You mean my $600 Hayes 240 won't communicate with TDDs?