sl@van-bc.UUCP (Stuart Lynne) (11/19/87)
After much hair pulling and two software updates I've finally figured out
why Bell Tech's ICC card wouldn't work with modems. The modular DB-25
connectors they use were wire incorrectly!
For those of you who have been having troubles getting modems working on
this card (with modem control) you might want to check this out. I don't know
if this is an isolated case or a generic problem. But all three of the
"Modem" connectors we received were identical (and incorrect). Another one I
have from an AT&T 3B is correct and works properly. (Note of interest, Bell
Tech uses the same type of modular connectors as AT&T, apparently from a
company called Nevada Western, they are not compatible with Mod-Tap modular
connectors.)
The problem was that the lines 6 and 7 going to pins 7 and 8 were swapped.
This effectively pulled DCD to GND, keeping getty or cu (or anyone) from
opening the port if modem controls were enable (ttyi versions). It also
seems to have the effect of sometimes "confusing" the electronics in some
modems (Hayes for me) so that they must be power cycled to regain sanity.
Incorrect wiring:
Cable DB-25
DCD line 6 ---- pin 7 GND
GND line 7 ---- pin 8 DCD
It should be
Cable DB-25
DCD line 6 ---- pin 8 DCD
GND line 7 ---- pin 7 GND
All of the connectors that I have are blue and are labelled "Modem" on a
large white sticker on one side.
Internally the incorrect wires were blue and red. The red going to pin 7,
and blue to pin 8. It should be red to pin 8, and blue to pin 7.
This can be accomplished by pulling the pins from the DB-25 connector and
re-inserting them properly. This usually is best done with a special tool
provided by the connector manufacturer to do this. But if you don't have it
you can try pushing the pin from the opposite side while using a needle to
release the tabs on the other side. If it won't come out, don't force it.
Ask some electronics shops for the extractor tools or ask Bell Tech to
replace them.
Bell Tech has also just finished a new set of software for the SysV 386.
This is release 0.6 (Beta Release). It seems to work better than either the
0.4 or 0.5 releases. I don't recommend 0.5 at all as it crashes the system. In
fact if you are using 0.5 and have 0.4 as well, go back to using the kernel
driver from 0.4. You can still use the /icc software from 0.5. With the 0.5
kernal driver trying to kill a process using an ICC port crashes the
system.
I've tried the new release under both Bell Tech's System V/386 and
Microports System V. It seems to work on both but I havn't done more than
simply verify that getty would come up for both terminals and modems and I
could dial out the modem lines. I will do some load testing on it over the
next week and see if there are any problems using it at 19.2 kbps to
terminals or Trailblazer modems. Hopefully some of the gremlins in earlier
releases will also have disappeared.
The big fix for this release is support for ttyiX type lines. Modem control
with optional dialout on ttiox. It is finally possible to have a normal
getty running on a modem and still dial out on a non modem control line.
Sighup/Hupcl seem to work as well. Three cheers to Bell Techs support staff
for finally getting it right *and* getting me the new version within a week
to try it out!
So for anyone out there who has been having problems with modems on Bell
Techs ICC card, ensure that your connectors are wired properly, and if you're
running under any System V / 386 call them up and ask for the 0.6 release.
For anyone thinking of using this card, it looks like I can once again
recommend it. It seems to work *very* well for terminals at 19.2 and with
this new software to support bi-directional use of modems without undue
problems.
Disclaimer: I am in no way associated with Bell Tech except as a purchaser
of their products.
--
{ihnp4!alberta!ubc-vision,uunet}!van-bc!Stuart.Lynne Vancouver,BC,604-937-7532