Siemens em 277 profibus communication module for simatic s7 200 system siemens 6es7277 0aa22 0xa0 this communication module is designed for use with units from the simatic s7 200 series for connection to the profibus dp as slave or from td 200 op tp pg pc s7 300 400 transmission speed 12 mbit s siemens 6es7277 0aa22 0xa0 em 277 communication module