Connecting to SMSC using SMPP

I am currently working on a visual basic SMPP project. I am trying to bind as a transciever to the SMSC but all i am able to do is make a TCP connection but when i send a bind Transceiver PDU it goes like data and is not recognised as a bind PDU. My PDU is built according to version 3.4 SMPP specs. Where is the problem? is it the format of the PDU? or am i missing some hearders somewhere?