Hi
I have looked and believe, Modbus is the comunication to use between Telemecanique and Siemens Plc's. Most Telemecanique and All S7 handle this protocol.
later
zan
You didn't specify which Tele PLC so I'm assuming its a Premium.
Unitelway is the integrated bus connection. There are other networks available that are PMCIA - Fipway, Modbus Plus, Jnet, Modbus. Then there is also a Modbus TCP/IP module. You also need to verify which processor you are using if there is more than one network as there are limitations.
I would suggest using the Modbus protocol. This communication language can talk to many many SCADA software programs, and other peripheral devices, e.g; setpoint controllers, temp controllers, and other controllers. Modbus is the way to go for compatibility.