What it is and what it does
The Siemens 6GT2891-0UE50 is a standard USB cable purpose-built as a short plug-in cable for connecting an RF1000 reader to a PC. It carries a USB type A connector on one end and a wire-to-board connector on the other, with 4 electrical cores in a 0.5 m length.
Where it fits
This cable is sized for the SIMATIC RF1000 reader family — the 0.5 m length keeps the reader close to the host PC, typical for a desktop or test-bench RFID setup. The wire-to-board end mates directly to the reader's internal connector; no field wiring or terminal block is involved.