>#2 - Port Death - It appears that on certain occaisions, a modem may
>hang-up/reset (&d3) and lose sync with the portmaster. The modem is still
>working, so it will answer the phone. However, with lost/no sync with the
>Portmaster, all the end user will get is either garbage or nothing. The
>only way to correct this problem seems to be to reset the port. If anyone
>has a fix for this one I'd LOOOOVE to know about it, since it's one of the
>things we can't directly solve!!
The easiest answer to do this is to set the pm2 serial port speed to the
modem vendor's "default" serial port speed. For example, the Hayes
Accura modem defaults to 115200 before doing any auto speed detection;
therefore if the pm2 is set to this same speed, there is never/seldom
a case of the modem-pm2 being out of sync. If you make any speed changes
make sure the modem table entry and the serial port speed are set to
whatever this default speed happens to be. I'd guess the majority of
current modems probably default to 115200.
There are a few modems on the market that allow you to lock the modem's
serial port speed to some specific value, and if the pm2 serial port
speed matches that locked speed, then lost/no sync issues should be
minimized as well. There aren't many of these though.
The majority of the modem vendor's tech support folks do not have a
clue as to what their default speed happens to be. To remove the guess-
work, remove any modem configuration set strings from one of your pm2
serial ports (e.g. "set s4 modem"), reset the pm2 serial port
'followed by' a power cycle of the modem. Dial into the modem with
the pm2 set at 115kb, then 56kb, then 38kb (etc) until you find a
speed match.
It would have been somewhat easier for all of us if Livingston would
monitor the activation of the DSR pin, and send the modem config
table entry each time the DSR pin comes alive. Since the pm2's DCD
pin floats high (DCD+) when the modem is powered off, watching for
the DCD transition to DCD- and then sending the modem setup string
after a short time delay would also solve some of these lost serial
port problems. Maybe this should be an RFE...
Rich
adar0@routers.com