Two things:

1) I would test this without using the RTS handshaking. Look up the command for the modem to turn off handshaking, or do it by resetting the modem to factory defaults. (by default it should be off in the factory settings. You can do a AT&F&WZ to fetch the factory settings, and write them into NVRAM, and reset the modem)

2) You don't have a carriage return at the end of the phone number. The modem isn't going to act until the CR or LF is seen.

As a debugging aid, I can suggest wiring up a null modem cable, and connecting it to another machine with a terminal program. That way, you can be assured that the port is spitting out what you think it should be.

--Chris

e-mail jcwren