bartm@cv.ruu.nl (Bart Muyzer) (04/25/91)
Hi,
I'm experiencing a problem with a HP37212B "Error Correcting Modem". I know
what causes it but I don't know what to do about it (except rebooting :-( ).
The modem is connected to a HP 9000/835 using a mux which (among others) also
attaches the system console to the system. This one works fine so I know it's
not the mux.
The problem is that the modem refuses to pick up the phone because the MDTR
is low. So it thinks the connected computer isn't ready and refuses to
answer. This situation occurs after the following sequence:
* user calls and logs in
* user initiates to be called back
* user hangs up and gets called back
* user works and hangs up
Now the modem never answers any further incoming calls. The RI(ng) light is on
during a ring but no answer...
The callback service uses the 'ct' program supplied by HP. As long as this
service isn't used, things seem to keep working fine. Even if I call the
modem, wait for it to start whistling and then throw down the hook things keep
working.
I used the following tricks to make the modem listen again:
* for a while, it worked to have the modem initiate a call using 'cu'. This
somehow reset the modem and it all worked again;
* it sometimes helped to kill a process called 'uugetty'. Init restarts it and
all is fine again;
* If this fails, the only thing left is to reset the 835.
A HP technician looked at the modem and even replaced the entire printboard,
but this didn't help. And I think (from the above) the modem is not to blame
but the 835 because it messes around with the MDTR signal.
Questions:
1. Can anybody provide an "off shelve" solution?
2. Is it possible that 'ct' doesn't properly reset things on exit?
3. Is there some way to flip the MDTR signal to "active" without rebooting?
4. Did I miss some modem configuration stuff (yes, I tried setting MDTR
always high using dipswithes on the modem, but this doesn't work either
since the modem picks up the phone but I never get a login prompt)
5. Are there any PD 'callback programs" available. If yes, where can they be
ftp'd from?
Any help will be appreciated.
>] Bart [<
--
Bart Muyzer(SysAdm), 3D Computer Vision, University Hospital Utrecht
Heidelberglaan 100, Room E 02.222, 3584 CX Utrecht, The Netherlands.
tel: +31-30-506711 (w), +31-3402-52157 (h) | "You never get a second chance
fax: +31-30-513399, e-mail: bartm@cv.ruu.nl | to make a first impression"lstowell@pyrnova.pyramid.com (Lon Stowell) (04/26/91)
In article <1991Apr25.154031.2013@cv.ruu.nl> bartm@cv.ruu.nl (Bart Muyzer) writes: >Hi, > >I'm experiencing a problem with a HP37212B "Error Correcting Modem". I know >what causes it but I don't know what to do about it (except rebooting :-( ). >The modem is connected to a HP 9000/835 using a mux which (among others) also >attaches the system console to the system. This one works fine so I know it's >not the mux. > >The problem is that the modem refuses to pick up the phone because the MDTR >is low. So it thinks the connected computer isn't ready and refuses to >answer. This situation occurs after the following sequence: The problem is NOT the modem, it is the [ software in ] the computer. As you note if DTR is low, the modem passes RI to the computer....(which is obviously ignoring it...). When you change the modem to set DTR high, the modem answers... [so the modem is performing perfectly normal] but you get no login....[which means the computer is dead] >* user calls and logs in >* user initiates to be called back >* user hangs up and gets called back >* user works and hangs up At some point after this, the computer [ software ] should be raising DTR to take another inbound call. This actually looks like a system problem...in that magically one user gets in, gets called back, and can access the computer. Something is drastically wrong with the exit routine which is leaving the port inoperative. Either the port should again raise DTR (so the modem can answer automatically) or it should detect RI, then raise DTR so the modem will answer. You don't have a modem problem, you have a software problem. Either that or your MUX is messing with the DTR signal from your computer. If you have a breakout, see if the computer has DTR on ( or will raise DTR if RI is high ).
franks@hpuamsa.neth.hp.com (Frank Slootweg CRC) (04/29/91)
Since the original posting is not present on our system (only the response from Lon Stowell) I responded by e-mail to the original poster. For the benefit of the net : If this is the scenario : - A process has a pending open on the call-in file of a port. - Another process has an open on the call-out file of the same port. - The second process terminates abnormally (i.e. is f.e. "kill"-ed). - DTR on the call-in file is not re-raised, i.e. the pending open will never succeed. then patch "p238" (for the Series 800, problem does not exist on the 300/400) is probably the solution. You can test if p238 will likely solve your problem by killing-and-restarting the process on the call-in file. If that re-raises DTR then p238 will probably solve your problem. The Service Requests are 5000-516948 and 4700-929398 and are in the Software Status Bulletin and HP SupportLine. Hope this helps. Frank Slootweg, RCE/Teamleader HP9000/HP-UX Support, Hewlett-Packard, Dutch Customer Response Center.
campbelr@hpcuhe.cup.hp.com (Bob Campbell) (04/30/91)
>I'm experiencing a problem with a HP37212B "Error Correcting Modem". I know >what causes it but I don't know what to do about it (except rebooting :-( ). >The modem is connected to a HP 9000/835 using a mux which (among others) also >attaches the system console to the system. This one works fine so I know it's >not the mux. I am not an expert at modems, but if your system has an AP card (the panel is connected to two cards using a "Y" cable) then only two of the ports (1M and 2M) are modem compatible. A non-AP mux should allow for modems on all ports. Also, the console is configured as a hardwire while your modem should be configured call-in/call-out. See the mksf man page for details. --------------------------------------------------------------------------- Bob Campbell Some times I wish that I could stop you from campbelr@hpda.cup.hp.com talking, when I hear the silly things you say. Hewlett Packard - Elvis Costello
bartm@cv.ruu.nl (Bart Muyzer) (05/06/91)
Hi,
Thanks to everyone who helped me with my modem problem. I got an official
patch of HP which seems to solve the problem. They also found out what
everybody told me...it was a bug in de mux driver.
Thanks again,
>] Bart [<
--
Bart Muyzer(SysAdm), 3D Computer Vision, University Hospital Utrecht
Heidelberglaan 100, Room E 02.222, 3584 CX Utrecht, The Netherlands.
tel: +31-30-506711 (w), +31-3402-52157 (h) | "You never get a second chance
fax: +31-30-513399, e-mail: bartm@cv.ruu.nl | to make a first impression"