< GO BACK Gefen Announces HDBaseT Signal Extenders Transmitting 4K, 1080p Posted on 2014-12-19·By Robert Archer Gefen 4K Ultra HD ELR-POL Extender with RS-232, Ethernet and IR (SKU: EXT-UHD-CAT5-ELRPOL). Posted in: HDBaseT, HDMI, Networks Tagged with: 4K, Gefen