The Siemens 6GT2891-4KH50-0AX0 is a pre-assembled connecting cable for the SIMATIC RF200 and RF300 RFID reader families, specifically built to link an RS232 reader to a PC. It runs 5 m, carries a 300 V rating, and terminates in a Sub-D female 9-pin on one end and an M12 female 8-pin on the other, with the 24 V side left as bare wire ends labeled for termination. That connector set is the whole fit story — if your reader is M12 and your controller is a standard DB9 serial port, this cable drops in without adapters.
Cable construction and environmental resistance
The jacket is black PUR, rated for trailing-bend applications up to 3 million cycles at a 75 mm bend radius. It resists grease and mineral oil, handles UV exposure, and is silicon-free — useful if you're running it near painting or potting lines where silicone outgassing causes adhesion failures. The braided shield is tin-plated copper, which keeps common-mode noise off the RS232 signal pair in electrically noisy cabinet environments. Operating temperature spans -30 to +80 °C across transport, storage, installation, and operation, so it's fine in unconditioned warehouse spaces or near ovens as long as you stay under that ceiling.
Sourcing decision
The 300 V rating covers the 24 V supply side with ample headroom. This is a quoted-to-order item through normal Siemens distribution — no surplus or broker channel needed. If you're cross-referencing from an older reader install, verify that your reader uses an M12 8-pin female and your PC or controller uses a DB9 male serial port; the cable bridges exactly that gap.