reeves-bill@CS.YALE.EDU (Bill Reeves) (02/24/91)
Hi. A friend just bought a small Tandy laptop word processor (a 200, I think, but maybe something as high as a 250 (?)), and he needs a way to transfer files to his ancient Mac 512K. We tried several public domain terminal emulator programs (Red Ryder 9.2, Term Emulator) and hooked the Tandy up to the Mac through the modem port, but we couldn't get the Mac to accept the characters the Tandy was sending. The people at Radio Shack have not been very helpful/knowledgeable - they say we need a program called Mac Terminal or something. So... Is what we are attempting possible? Do we need more software, or more hardware? (The Tandy has an RSC232 port (or whatever they're called), the Mac's modem port is the old 8- or 9-pin thing, and my friend went all over town getting cables to connect the two machines) Can anyone help? All responses will be greatly appreciated! Thanks a lot! -- Bill Reeves, reeves-bill @ cs.yale.edu
furmanm@hotcity.uucp (Michael Furman) (03/04/91)
Bill:
I just happen to have the pin-outs of thhe Mac 8-pin modem port. I
can't find my RS-232C specs right now, so I may need to follow this message
with the Tandy side of the connection to make sure it will work. What you
need anytime that you are trying to connect any 2 computers that are different
together, it is a good idea to have a RS-232 break-out box, and also, a line
monitor ( you put it in line with the cable, and it tells you the activity on
the major lines)
You also will need a plug that goes into the Mac that has wires on the other
end so that you can try different ways of connecting things.
Here is the Mac pinout:
Pin Function
------- ----------------------
1 Handshake out
2 Handshake in
3 Transmit data minus (ground)
4 Signal ground
5 Recieve data minus
6 Transmit data plus
7 Status line (goes to DCD)
8 Recieve data plus
What you need to do on the Mac, is turn the "handshake" off. It looks as if
the Mac outputs are "current loop", and that gets a little bit complicated.
The Tandy side is no problem, since it is standard RS-232. I don't know that
much about the Mac, so, if anyone else can, add to this. You might also want
to go to a Mac.hardware newsgroup and ask them.
I hope that this is of some help. I do have more info, but I will need to find
it while I'm offline, and call back with more info for you.
By the way, you can get cables that convert RS-232 to Mac, but I'm sure that
you have one of these allready, and that it probably didn't work.
Michael Furman-- out here in "sunny" California (It's been raining since
Wednesday-- for a longer time than since that beginning of the drought)tswift@well.sf.ca.us (Theodore John Swift) (03/15/91)
furmanm@hotcity.uucp (Michael Furman) writes: > What you need to do on the Mac, is turn the "handshake" off. Actually, for RS-232 work, you can just ignore them, since they're only used (or necessary) for high-speed clocked stuff. The following information is from _Inside Macintosh Vol. 4_, p. 248. > It looks as if > the Mac outputs are "current loop", and that gets a little bit complicated. > The Tandy side is no problem, since it is standard RS-232. I don't know that > much about the Mac, so, if anyone else can, add to this. You might also want > to go to a Mac.hardware newsgroup and ask them. The Mac's serial ports are RS-422 (or 423, according to _IM4_), not to be confused with the old (generally 20 milliamp) current loop. RS-422 uses a differential pair (TX+, TX-; RX+, RX-) to transmit data: when TX+ is "high", TX- is "low", and vice-versa. "high" is +5V and "low" is -5V, I think. RS-232 generally likes about +-12V, but will work with much less. To "fake" RS-232 on the Mac, connect TX+, RX+, and Ground to the appropriate lines on your RS-232 side. Here's the pinout as listed in _IM4_; It basically agrees with Michael's, with the exception of pins 3, 5, and 7. Pin Function my comments ------- ---------------------- ----------- 1 Handshake out 2 Handshake in or external clock 3 Transmit data minus not ground 4 Signal ground 5 Recieve data minus not ground 6 Transmit data plus 7 Not Connected according to _IM4_ 8 Recieve data plus As Michael recommends, it's good to have a breakout box to troubleshoot, but if one is not available, a bit of experimentation with these lines should do the trick. Just about any terminal emulator on the Mac should work. Good luck. -Ted -- ---------------------- Ted Swift tswift@well.sf.ca.us "You bally well are informed, Jeeves! Do you know everything?" "I don't know, sir" ~P.G. Wodehouse