Null modem help – ADM-3A
8 messages in this thread
Hi–
I have a strange problem. My partner and I are doing a custom application
for a customer that involves hooking up a dumb terminal to the Amiga.
Originally, we were using a Televideo of some sort, but it died. So, were
able (in an emergency) to find an old, working Espirit lying about. It is
an ADM-3A clone, and offers other emulations that I don't recognize:
HAZ(eltine?)1500something; VP-2+; REG25…
At any rate, we would like to hook this baby up to the serial port, but
it does not respond. The Televideo worked with just lines 2,3,7, but this
one is much more finicky. Anyone have any ideas?
Jonathan
– via Whap!
Sure, just find a manual for the Esprit. Maybe you'll find one in the
local Computer Museum. 🙂 But seriously, it might require something
else, like a local jumper between 4 and 5 or another between 6 and 20.
John–
Thanks for the reply, will try jumpers at those locations. Hope to be out
of RS-232 hell soon.
Jonathan
What a collection of terminals. HAZELTINE 1500 is certainly an odd one but
may be the best to use. In any event, it probably wants DTR/DSR
handshaking. Just Jumper pins 4 to 5 and 6 to 20 and things should work
quite nicely. Boy, the memories these terminals seem to dig up. I did a
lot of work on real live Hazeltines and ADM-3A's attached to 300 baud
handset cradle modems. Good luck.
John A. Toebes, VIII – via Whap!
John–
Thanks for the information. Should I jumper 4<–>5 and 6<—>20 on both
sides? I assume that the rest should be 2+3 crossed, and 7.
jonathan
I have an old ADM-3 here that I use now and then for debugging stuff, or
trying to get my PDP running. I found that in order to use it as a
terminal I have to add in a null-modem connector (swap pins 2 and 3).
I have used it to log on here before, with a null-modem connection to my
actual modem. This peculiarity may be unique to my unit (it was used by
electronics students to learn RS232 interfacing, and may have been
permanantly altered), but I don't think so. Try using the opposite pins
for 2 and 3 and see if it works.
I also have operated just fine without pins 4,5,6, or 20 connected. (may
also be hacked internally)
I also have the maintenance manual for it if you have any specific problems
you need to fix. (Never thought I hear about one of these here)
Greg
Greg,
Thanks for the information. The terminal in question is not technically an
ADM-3A…however, I also found an original ADM-3A manual, and it helped
with some of the setup.
Jonathan
Check your baud rates. Not all terminals had the same default baud rating.
– Well Whap! Me Silly….