The Siemens 6ES7902-2AC00-0AA0 is a SIMATIC S7/M7 cable purpose-built for point-to-point TTY connections between two 9-pole D-sub interfaces, running 10 m in length. This is a serial communication cable for the TTY (current loop) physical layer, which is a legacy but still-deployed interface in many S7-300/400 and M7 systems for connecting programming devices, operator panels, or other controllers over longer distances than standard RS-232 allows.
The 10 m cable length is the full point-to-point run, not a pigtail — it covers the distance between a controller rack and a programming station or remote TTY device without needing an extension or coupler.