How and what would you need to make a chat program that works over a lan? DOS or Windows help will be fine.

I was wondering if it is possible to use Zmodem, Xmodem, and Ymodem in DOS, and if so how? I would prefer a simple way because I'm in between beginner and intermediate. I'm trying to use this code to make a DOS terminal program that dials to another computer and waits for calls and allows the 2 computers to chat and send/receive files.

Thanx