The 6ES7902-1AD00-0AA0 is a 15-meter RS232C point-to-point connection cable with 9-pin D-Sub connectors—plug at one end, socket at the other. It links a SIMATIC S7/M7 CP 340 or CP 341 serial communication processor to an RS232 partner device—an HMI panel, barcode scanner, modem, or third-party controller—across the longest standard RS232 length in the 6ES7902-1 series.

Is RS232 reliable at 15 meters?

The RS232C standard specifies a maximum cable length of roughly 15 meters at 19.2 kbps—and this cable is built to that exact limit. Siemens pre-assembles and factory-tests these cables, so the connector termination quality and shield bonding are controlled, unlike a field-terminated DB9 connector where wiring errors and cold solder joints can eat into the already-thin noise margin at maximum length. At lower baud rates (9.6 kbps or below), 15 meters is well within the electrical margin. If the partner device is more than 15 meters away or the baud rate exceeds 19.2 kbps, RS422 is the safer physical layer—use the 6ES7902-3 series instead.

How does this RS232C cable differ from the TTY and RS422 variants?

All three use 9-pin D-Sub connectors, but the electrical interface is fundamentally different: RS232C (6ES7902-1 series) uses single-ended voltage signaling, best for short-to-medium runs up to 15 meters. TTY (6ES7902-2 series) uses 20-mA current-loop signaling, immune to voltage-drop noise over long runs. RS422 (6ES7902-3 series, 15-pin) uses differential signaling, rated for up to 1,200 meters. The connector is keyed—a 9-pin RS232 cable will not mate with a 15-pin RS422 port. Match the cable series to the CP module's port type.