Path: utzoo!attcan!uunet!cs.utexas.edu!usc!apple!olivea!oliveb!bunker!wtm
From: rbarth@tumtum.cs.umd.edu (Dick Barth)
Newsgroups: misc.handicap
Subject: TDD
Message-ID: <15396@bunker.UUCP>
Date: 5 Nov 90 15:24:12 GMT
Sender: wtm@bunker.UUCP
Reply-To: rbarth@tumtum.cs.umd.edu (Dick Barth)
Distribution: misc
Lines: 50
Approved: wtm@bunker.UUCP
Fidonet: Silent Talk Conference

Index Number: 11494

In private mail quoted in a previous Digest, 
George.Forster@f104.n268.z1.fidonet.org (George Forster)  writes,

   Several years ago you left me a memmo from your handicapped exchange 
   pertaining to making my original ibm pc a tdd with some parts from radio 
   shack. Well i have looked all over and never found the parts. If you 
   remember the pc (mine) has the tape jack that is similar to the keyboard 
   plug. but i have never found the parts.

That particular telephone modem (I assume that's what you've been unable to
find) may not be in stock any more. Best bet, if you want to find one, is
probably to try a variety of Radio Shack stores to see which might have them
sitting around. Often parts that have been dropped from the catalog are sold
off at very good discounts. You might also advertise in electronics hobby 
newsletters if you have one of those in your area, or via the "wanted"
newsgroup on Bitnet.

If all else fails, remember that the only reason John Spalding designed
around that particular model of telephone amplifier is that it was available.
You can use a current version just as well. Its only purpose is to provide a
legal interface to the telephone line - one that meets Part 68 of the FCC
rules - and a little amplification. The important things are to make sure
the levels from the phone line into the computer, and from the computer
into the phone line, are both correct. With a different amplifier you will
probably have to use different values of resistors, and you'll have to
poke around inside the chassis to find the appropriate points to connect
to, but it shouldn't be terribly difficult. If you can find a technically
oriented salesman at the Shack (granted, this may be tough to do) he or
she might be willing to lend a hand. If not, try the local ham radio club.
there are always a few tech junkies in a ham club willing to lend a hand 
on something like that.

   Also i have a texas instrument silent 700 data terminal that has a cradle 
   adaptor for a phone. Do you know if this instrument could be converted to a 
   tdd.

Probably not. The Silent 700 is an ASCII machine and TDDs use Baudot. You'd
have to tear into the innards of the 700 to modify its code generation
software, and I don't imagine that would be an easy thing to do. 

   thanks, George Forster, Stroudsburg

You're quite welcome. Let me know how you make out.

--- 
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)