jbr@key.COM (Jeff Rubin) (05/04/91)
I have a Practical Peripherals 9600SA modem (Rom version 1.29) which I
use to connect to a Telebit T2500 (Rom version 6.1). I connect using
V.32/V.42/V.42bis. The T2500 is the originating modem (I used callback
security). The connection works okay for a period of time and then
the connection gets broken. The 9600SA reports various causes (S86 = 4:
physical carrier loss, or S86 = 12: normal disconnect initiated by remote
modem, or S86 = 13: remote did not respond to repeated message; after 10
attempts local modem terminated call). Upon a suggestion from Telebit
technical support, I tried three things with the following results:
1. Turn the speaker on and listen for retraining.
Indeed, the connection hangs and then drops at a time when there
are (what I guess are) retrain tones on the line. In fact, when
things are okay, there are no tones; when transmission stops there
are a few bleeps, and then a long continuous tone, and then the line
is hung up.
2. Try MNP.
Again, when okay there are no tones, then when the trouble occurs,
there are a couple of beeps, then about 1/2 minute with no beeps,
then another couple of beeps, and then hangup.
3. Try no V42 no MNP
This time when the trouble occurs, there is simultaneously a burst of
garbage characters and beep tones. This is followed by recovery in
which there is normal transmission.
4. With a person at each end, find out who is hanging up first
I haven't been able to do this yet.
I should mention that the problem occurs even if I don't use V.42bis.
On a previous call to Telebit tech support, they suggested I try
ATJ6S140=1 to cause the T2500 to not attempt to retrain. This didn't
solve the problem. I also tried simultaneously doing AT&B0 on the 9600SA
which is supposed to disable retraining. Still no luck.
Does anyone know what's happening and how to work around it?
-- Jeffjim@shograf.com (jim morris) (05/05/91)
From article <2583@key.COM>, by jbr@key.COM (Jeff Rubin): > I have a Practical Peripherals 9600SA modem (Rom version 1.29) which I > use to connect to a Telebit T2500 (Rom version 6.1). I connect using > V.32/V.42/V.42bis. The T2500 is the originating modem (I used callback > security). The connection works okay for a period of time and then > the connection gets broken. The 9600SA reports various causes (S86 = 4: >.... > Does anyone know what's happening and how to work around it? > > -- Jeff Well I don't know whats happening, but I have exactly the same problem with an Intel 9600ex <-- T2500 connected 9600/LAP-M/COMP I have call back as well so the setup is identical, except that I am using the Intel 9600ex, this would stongly suggest that the T2500 is at fault!! I also have a T1600 that calls me back, and I have never had that drop a connection. If anyone can solve this problem I would also be very grateful. Jim -- Jim Morris, E-Mail: jim@shograf.com Voice: (415) 903-3887 _ SHO graphics. Practical PEX
mkahl@world.std.com (Michael Kahl) (05/05/91)
In article <2583@key.COM> jbr@key.com () writes: >I have a Practical Peripherals 9600SA modem (Rom version 1.29) which I >use to connect to a Telebit T2500 (Rom version 6.1). I connect using >V.32/V.42/V.42bis. The T2500 is the originating modem (I used callback >security). The connection works okay for a period of time and then >the connection gets broken. The 9600SA reports various causes (S86 = 4: >physical carrier loss, or S86 = 12: normal disconnect initiated by remote >modem, or S86 = 13: remote did not respond to repeated message; after 10 >attempts local modem terminated call). I have exactly the same problem, only I have a Hayes Ultra 96 rather than a Practical Peripherals 9600SA. I've also heard of a MultiTech user having the same problem, plus I see that jim@shograf.com has also replied to your post reporting the same thing with an Intel 9600EX. The common denominator in every report I've seen is that the other modem is a Telebit T2500. That says something, I think. I don't have a solution. The best workaround I have found is to limit the connection to 4800 rather than 9600. Not ideal, but for what I do 4800 with MNP5 or v.42bis is plenty fast enough most of the time. I tried this on the advice of someone else who reported the same problem, and it works. The problem seems to be somehow specific to 9600 and doesn't show up at 4800. -- Michael Kahl, Symantec Corporation mkahl@world.std.com -or- 75236.3146@compuserve.com Disclaimer: Keep this quiet; what my employer doesn't know won't get me fired.
brian@telebit.com (Brian Lloyd) (05/05/91)
I am going to look into the issue of T2500's dropping connections unnecessarily or improperly. Thanks for the discussion. I will report back. -- Brian Lloyd, WB6RQN Telebit Corporation Network Systems Architect 1315 Chesapeake Terrace brian@napa.telebit.com Sunnyvale, CA 94089-1100 voice (408) 745-3103 FAX (408) 734-3333