Trasnfer data using Modem

[ayuba asia]

I need to develop a system that can transfer data from 1 pc to another pc using dialup because the user dont want use any FTP service.. so i cannot use any isp services so i think i need to create a service at one side that can accept called from another side and get the transaction and stop the connection... and i need to create i utlity that can dialup and get data and disconnect.. 2 utility 1 dialup and 1 accept call.. how do transfer this to my coding any example or source that i can use.. in c#... or is there any otherway for me to settle this issue. thanks