We have slave devices which talk modbus RTU on RS-485/422. We have gateway devices to convert RTU to Modbus TCP on ethernet. Now we want to put modbus over a dial-up link. I presume that RTU will be unreliable over dial-up because of the timing issues, so we're thinking about putting Modbus TCP over dial-up. Is this feasible? Are there any gateways/intelligent modems that will do this?