I have no idea, but if you have the modem and a Series 7 why not try it and see?Start off with basic settings such as:
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Name - 3Com Global
Speed - 57600
Connect - PC Card (or whatever it's called, I don't have a 7)
Fax Class - Auto
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Init (reset) - ATZ (or try AT&F)
Data - (blank)
Fax - (blank)
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Flow - Hardware (RTS/CTS)
Terminal (DSR/DTR) [X] checked (but also try unchecked)
Carrier (DCD) [X] checked (but also try unchecked)
Type - Fixed line
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If you are not getting anywhere, try using Comms to send AT commands to it. You should even be able to dial your ISP and receive and respond to Username and Password prompts, but you won't be able to negotiate the internet protocols with Comms.
If you have a laptop with which you have used the modem, the modem log file might give an indication of the initialisation strings sent to the modem.
On the other hand, perhaps someone has personal experience with this modem :-)
Mike