i used a r300 tdma ericsson cellular phone, to send sms , i don't know if the phone you're using has the same connector, but the r300 has a serial interface in the connector at the bottom, only the protocol is standard the voltage levels are to 3v to 0 , the way to dial a number is sending thru hiperterminal or another comunicactions software the string Atdt XXXXXXXX where X is the number to dial
if you want to use other functions of the phone, nned to refer to the TIA docs
, i currently have the docs for tdma if you need msgme pls