- APP-51 electronic hook switch cable for remote desk phone call control (answer/end)- Eliminates the need for an HL10 handset lifter- Works with Polycom desk phones- Compatible Plantronics headsets include Savi 700 series, CS500 series, and Voyager Legend CS- Replaces the APS-50 cable and features compatibility with the Plantronics on-line indicator accessory - Plantronics Part: 38439-11