PeteSmithTyco
Programmer
Hi all.
I've got a question. It's already been raised with USR Support, but I thought I'd ask outside, to see if anyone else has seen it.
We're using the modems (Messenger 56k) in a phone test system. There are 8 modems in a box, connected via an 8 port RS232/USB converter.
We have discovered an alarming feature, if one of the modems is connected to a phone line that already has modem/fax traffic on it.
I have run some tests where 2 modems are connected & negotiated to each other via a mini-exchange (BT Ultimate 106). A third modem is teed off the first two (in a very similar way to the way it's used in the field). If this happens, then the modem will go any time between 1 second and 10 minutes before it crashes.
This crash takes the form of the modem becoming unresponsive. The local echo still works, but no commands are accepted.
Trying to reset the modem by putting it in AT&D3 mode, and toggling the DTR line, or sending ATZ do not work. I've also tried +++<1 sec pause> and ATH.
The affected modem then needs to be powered down before it works again.
I've confirmed that the problem isn't a comms issue in the system, because the modem tests *only* fail when connected to a phone line which contains modem (and possibly fax) data. If the modem has dialtone, or nothing at all, it will run flawlessly for days on end. If modem data is present, it will consistently crash within 10 minutes, quite often a lot less than 10 minutes.
If this failure occurs, the modem is unresponsive to the Windows diagnostic system, and restarting the USB hub does not restore comms: only power cycling the modem works.
Given the problem occurs on these modems, which have CLI support (which therefore means the modem is not disconnected from the line with a relay, as the old fashioned modems tended to be), I think the DSP or processor inside the modem is seeing the modem comms, and becoming confused.
Any ideas?
Thanks.
Pete.
I've got a question. It's already been raised with USR Support, but I thought I'd ask outside, to see if anyone else has seen it.
We're using the modems (Messenger 56k) in a phone test system. There are 8 modems in a box, connected via an 8 port RS232/USB converter.
We have discovered an alarming feature, if one of the modems is connected to a phone line that already has modem/fax traffic on it.
I have run some tests where 2 modems are connected & negotiated to each other via a mini-exchange (BT Ultimate 106). A third modem is teed off the first two (in a very similar way to the way it's used in the field). If this happens, then the modem will go any time between 1 second and 10 minutes before it crashes.
This crash takes the form of the modem becoming unresponsive. The local echo still works, but no commands are accepted.
Trying to reset the modem by putting it in AT&D3 mode, and toggling the DTR line, or sending ATZ do not work. I've also tried +++<1 sec pause> and ATH.
The affected modem then needs to be powered down before it works again.
I've confirmed that the problem isn't a comms issue in the system, because the modem tests *only* fail when connected to a phone line which contains modem (and possibly fax) data. If the modem has dialtone, or nothing at all, it will run flawlessly for days on end. If modem data is present, it will consistently crash within 10 minutes, quite often a lot less than 10 minutes.
If this failure occurs, the modem is unresponsive to the Windows diagnostic system, and restarting the USB hub does not restore comms: only power cycling the modem works.
Given the problem occurs on these modems, which have CLI support (which therefore means the modem is not disconnected from the line with a relay, as the old fashioned modems tended to be), I think the DSP or processor inside the modem is seeing the modem comms, and becoming confused.
Any ideas?
Thanks.
Pete.