Siemens 6ES7137-6AA00-0BA0 - Communication module for serial connection RS422, RS485 and RS232, Freeport, 3964 (R), USS, MODBUS RTU Master, Slave, 115200 Kbit/s
Siemens 6ES7137-6AA01-0BA0 - Communication module for serial connection RS422, RS485 and RS232, Freeport, 3964 (R), USS, MODBUS RTU Master, slave, max. 250 Kbit/s, suitable for BU type A0
Siemens 6GK7542-6VX00-0XE0 - Communications Processor CP 1542SP-1 IRC IEC-60870-5-104 or DNP3 protocol BusAdapter required