Siemens Plc Tcpip Communicaton

I have been asked to provide a driver to interface with a Siemens S7/300 series PLC using a CP 343 ethernet card. I can talk to modicon and telemechanique PLCs using a TCPIP socket program, but when i try to use the same program with seimens, i fail to get a socket connecton.
I am told that i can use TCP Native or UDP

I can ping the PLC's IP address

I have very little experience of step-7 so i may have a set up problem

Has anyone ever tried this before, or is there a better way to go.

This is a preliminaryn query prior to going the S7 ie route

Hello ColinDavies;

You can ping the PLC's IP address because you have a correct physical setup; you cannot talk to the CPU through the CP343-1 because you are not using the correct protocol. Siemens' Industrial Ethernet is incompatible with Modbus/TCP (Modicon and Télémécanique) ot Allen-Bradley's Ethernet. The details are not within my level of expertise, I am talking from painful experience. We had to use OPC or protocol converters in different projects to get these different flavors of Ethernet comms to work together in different projects.
You can find details on Siemens' Industrial Ethernet on the Siemens support Website:

http://www4.ad.siemens.de/csinfo/li...nfo&wttree=productnodes&lang=en&objID=4000024

Hope this helps,
Daniel Chartier