IMATIC ET 200SP, CM PTP communication module for serial connection RS-422, RS-485 and RS-232, freeport, 3964 (R), USS, MODBUS RTU master, slave, max. 250 Kbit/s, suitable for BU type A0, pack quantity: 1 unit
https://mall.industry.siemens.com/mall/cs/cz/Catalog/Product/6ES7137-6AA01-0BA0