The Siemens 6ES7902-2AG00-0AA0 is a SIMATIC S7/M7 cable for point-to-point connections using TTY signaling, terminated with 9-pole D-sub connectors at both ends. It runs 50 m, which is the full-length variant for this cable family — enough to bridge a remote I/O rack or a panel-to-panel link in a medium-sized line.
Physical fit
At roughly 1 526 g and 50 m, this cable is heavy enough that you will want to support it with cable trays or tie wraps along the run — do not let it hang unsupported from the D-sub connectors. The 9-pin D-sub pin assignments follow the Siemens TTY pinout; if you are replacing a third-party cable, check the wiring diagram against your existing connector to confirm the pin-for-pin match.