Miami Not finding my modem

[Castellen]

Check your hardware driver (serial.device, etc) actually works with your modem.
Get a terminal prog like NComm or Term and set it to use the same hardware device as Miami was, and see if you can talk to the modem.
E.G. entering AT&V should make the modem list it's config.
That is if Supra modems are Hayes compatible???

If there are still no comms with the modem, try a different modem and cable.
Failing that, you may have a motherboard fault.  Maybe a CIA problem.  Also check the -12V supply to the motherboard.

[Castellen]

If it connects with a terminal prog, than I can't see why Miami shouldn't work properly.
Perhaps try putting ATZ only in the init string to reset the modem, and let the modem use all it's internal defaults?

8n1.device is a good suggestion, I used to use it with my hayes compatible modem back in the days when I used dialup internet
I can send you a copy if you like, drop me an email.