SIMATIC S7-1200, CM 1243-2 Communication Module AS-Interface Master according to AS-i Specification V3.0. SIMATIC S7-1200 Basic Controller - flexible due to a variety of communication options. To ensure data transmission to various systems, a range of communication modules is offered for the SIMATIC S7-1200, from the RS232 interface to AS-i and PROFIBUS connections in master or slave mode. This guarantees a wide range of applications for the SIMATIC S7-1200.