The Siemens 6ES7540-1AD01-0AA0 is an active-production CM PtP RS232 BA module for the S7-1500 platform. It provides one RS-232 serial port on a 9-pin D-sub, supporting freeport, 3964(R), and USS protocols at a maximum of 19200 bit/s. That baud rate is fixed for the protocol modes – match it to your downstream device before specifying the BOM line. The module plugs directly into the S7-1500 backplane and is powered from the backplane bus. The 9-pin D-sub is pinned per standard RS-232; standard straight-through cables work.
Integration notes
Spring-cage terminals are not used – the RS-232 port is a fixed 9-pin D-sub. Strip length and termination are per standard RS-232 practice: shield grounded at the panel end only. The module is hot-swappable in S7-1500 racks; no power down is needed for replacement. Protocol selection (freeport, 3964(R), USS) and baud rate (19200 bit/s) are configured in TIA Portal. This module uses RS-232 on a 9-pin D-sub.