dial-up communication

Question

hi all, i need a way to communicate through phone lines. following is the setup i have. two pc's which are both connected to two phone lines through modems. none of them has internet facility. i want one PC to start a communication session by dialing the other PC's number. once the connection is established, i want to communicate with the other PC. ( through sockets preferebly-Windows sockets). this applies to both local and remote PC. Remote PC should be able to start a communication session in the same way. this is similar to the communication done in hyperterminal. but i cant use it here since i want to programe the above functionality in to the application i built (Written in c# and vc++). can PPP protocol be used here. is there any modules available for this. is there any API for the hyperterminal communication protocols (z modem) thank u in advance. manusha