Trying to communicate with a GSM modem for sending SMS messages from my web app.

When I access the GSM modem from SecureCRT (using a serial option to connect) everything seems to be working fine.
I am sending the following commands:
AT+CMGS="123456789" (where 123456789 is the recipient's phone)
and then I get a prompt to type text. I type the text and hit ctrl+z to send. works like a charm.

I am looking for the same functionality under PHP, and found this class:

Unfortunately I can't get it to work. No errors or anything - just nothing happens.

I was wondering if anyone has ever had any experience with this.

By the way - I am not restricted to PHP. ANY solution would do.