What it is and where it lands
The Siemens 6GT2891-6UH20 is a pre-assembled RS232 communication cable that connects an RF1040R or RF1070R reader to the RF120C communication module. It's a 4-core LiYCY cable, 2 m long, with a braided shield of tin-plated copper wires and a PVC jacket. One end terminates in a D-sub male 9-pole connector at a 45° angle; the other in a PicoBlade 51021 5-pole. That D-sub angle matters when you're routing inside a tight enclosure — it keeps the cable profile low against the panel wall. Rated for 300 V maximum, which is the UL AWM 2464/2517 listing for the cable itself (cable only, not the assembled plug). That 300 V rating covers the signal isolation between reader and module in an industrial environment.
Fit and routing constraints
Fixed at 2 m — no field-cut length adjustment. The minimum bend radius is 69 mm for both single and multiple bends, so plan your cable tray or trunking path with that radius in mind. Loop resistance is 130 mΩ/m maximum, which is fine for RS232 at this distance. Operates from -15 to +80 °C; stores and transports from -30 to +80 °C. That covers most indoor panel environments and unheated warehouses. Flame resistant per IEC 60332-1-2, so it passes the vertical-wire flame test for control panels. Silicon-free and UV-resistant, which matters if the cable passes near a window or UV-curing station.
What it resists and what it doesn't
Resistant to water, mineral oil, and UV radiation. Not halogen-free — the PVC insulation will produce hydrogen chloride gas in a fire, so factor that into your panel fire-suppression strategy if you're in a zone that mandates low-halogen cabling.