Prolinx Gateways makes this type of device. Their web site is "www.prolinx-gateways.com":www.prolinx-gateways.com It should be noted that this device is a gateway for passing infomation from one type of network to the other type of network. It is note a true bridge, in that you cannot pass programming
commands, etc over it, but only predefined trnasfers of information such as bits, integers, etc. Hope this help you.
"www.fieldserver.com":http:www.fieldserver.com can provide a solution to Profibus DP or multislave to Modbus TCP/IP, ASCII or RTU. This can be achieved in a single unit, with a point capacity of 40 000.