Scott.Bechtel@f222.n105.z1.fidonet.org (Scott Bechtel) (08/28/90)
Index Number: 9985
[This is from the Silent Talk Conference]
I have an Amiga 2000 and was wandering if anyone would know of a
program/hardware addition that I could use to talk to my tdd friends with?
I have heard of this for some ibm's so I think it would be possible. If not,
maybe I will be able to make something someday. SB
--
Uucp: ..!{decvax,oliveb}!bunker!hcap!hnews!105!222!Scott.Bechtel
Internet: Scott.Bechtel@f222.n105.z1.fidonet.orgScott.Bechtel@f222.n105.z1.fidonet.org (Scott Bechtel) (08/28/90)
Index Number: 10001
[This is from the Silent Talk Conference]
I have an Amiga 2000 and was wandering if anyone would know of a
program/hardware addition that I could use to talk to my tdd friends with?
I have heard of this for some ibm's so I think it would be possible. If not,
maybe I will be able to make something someday. SB
--
Uucp: ..!{decvax,oliveb}!bunker!hcap!hnews!105!222!Scott.Bechtel
Internet: Scott.Bechtel@f222.n105.z1.fidonet.orgrbarth@tumtum.cs.umd.edu (Dick Barth) (09/04/90)
Index Number: 10050
In Digest # 1454, Scott Bechtel writes:
I have an Amiga 2000 and was wandering if anyone would know of a
program/hardware addition that I could use to talk to my tdd friends with?
I have heard of this for some ibm's so I think it would be possible. If
not, maybe I will be able to make something someday. SB
I have to assume that your Amiga does NOT have a cassette port; most newer
computers don't. If my assumption is wrong, let me know; I'll have a couple
of other suggestions for you.
TDDs use the older Baudot code, not ASCII. They also use a modem that isn't
compatible with standard ASCII modems. So, you need to get a TDD modem and,
depending on how you do that, you may need to write a comm program that does
code conversion.
The simplest solution is to buy a commercial TDD modem that has built-in
code conversion. These connect to a standard serial port and to a phone line.
They provide both TDD and Bell-103 compatibility and are available from two
sources I know of. These are Ultratech and Krown Research. If you were
using an MS-Dos machine, you could also use a unit from Phone-TTY that comes
with software to run on that kind of a computer.
The TDD uses frequency-shift keying (FSK) same as the -103 type modem.
You can modify an older Bell-103 modem to use TDD frequencies (1400 MARK
and 1800 SPACE), recognizing that the send tones have to shut off within
a couple hundred milliseconds after the character has been sent. This is
because TDD uses the same tone pair in both directions, therefore tones
have to squelch so you can hear the other guy.
You can also build a simple FSK modem from scratch using such chips as
the EXAR XR2206 and XR2211. Not difficult; ask EXAR for the modem
designer's manual and poop sheets for these chips.
Code conversion is just table lookup; if you can write a simple comm
program (which doesn't need to be interrupt driven at 45 baud) you
should have no trouble doing the rest.
For a description of the commercial TDD modems on the market, download
the file COMPARE.TTY from file area two of the HEX BBS. For code
conversion software in the C programming language, download BAUDOT.C
from the same place. And if you finish this project and want to share
your design, please let me know.
Happy hacking.
-----------------------------
Richard Barth, W3HWN, rbarth@tumtum.cs.umd.edu
Handicapped Educational Exchange... (301) 593-7033 (TDD & 300 baud ASCII)
(301) 593-7357 (300/1200 baud, 8N1)Leon.Adato@f3.n157.z1.fidonet.org (Leon Adato) (09/18/90)
Index Number: 10428
[This is from the Silent Talk Conference]
I have a list of 4 companies that make a hardware piece to allow your
modem to use baudot code. Some are only usable on the IBM, others
are fine for any PC. I'm including them all for anyone elses benefit.
Here goes:
Integrated Microcomputer Systems -Uni-PTC
internal modem for IBMs only
software provided
no download or upload
$499.00 plus s/h
Krown Research- Model SM85
external modem (not Hayes compat.)
used with any PC with an RS-232 serial port
can be used with any communications software
only ASCII downloads and uploads, won't support Xmodem
$349.00 +s/h
requires a serial cable (not provided)
Phone-TTY- Model CM-4
external modem
RS-232 compat.
runs only on IBMs (& clones) due to software limitations
can be programmed to work with other computers, though
$349.00 +s/h
needs serial cable (not provided)
Ultratec- Intele-Modem
external (hayes compat.)
used with any PC with RS-232 serial port
used with any commmunication software
cost: under $200.00 (I don't have it listed)
Phone numbers:
Integrated Microcomputer Systems- v:301-948-4790
TDD/ASCII 300: 301-869-6391
Phone-TTY- v:201-489-7889
TDD:201-489-7890
Krown Research- v/TDD: 213-839-0181
Ultratec- 800-482-2424
608-273-0707 BOTH lines are v/TDD
I hope this helps. Let me know if you have any questions
Leon Adato
(216)381-0188
@Cleveland Freenet: aa598
PC-OHIO
NEOPCUG
Nerd's Nook
--
Uucp: ..!{decvax,oliveb}!bunker!hcap!hnews!157!3!Leon.Adato
Internet: Leon.Adato@f3.n157.z1.fidonet.org