The Poly APP-51 Electronic Hook Switch Cable (85Q60AA, part 38439-11) enables remote call answer and end directly from a compatible Poly wireless headset when used with Polycom SoundPoint IP and VVX desk phones. By connecting the headset base to the phone's headset port, the APP-51 electronically signals the phone to go on- and off-hook — eliminating the need for a physical handset lifter. It is TAA compliant and compatible with the Poly Online Indicator busy light accessory. Key Features Hands-Free Auto-Answer: Electronically signals the desk phone to answer and end calls when you press the button on your wireless headset — no HL10 lifter needed. Broad Polycom/VVX Compatibility: Works with SoundPoint IP 320, 321, 330, 331, 335, 430, 450, 550, 560, 650, 670 and VVX 300, 310, 400, 410, 500, 600, 1500. TAA Compliant: Suitable for US federal and government procurement. Online Indicator Compatible: Works with the Poly busy light accessory to show headset in-use status to nearby colleagues. Replaces APS-50: Direct successor to the older APS-50 EHS cable for Polycom phones. Technical Specifications Specification Detail HP SKU 85Q60AA Poly Part Number 38439-11 Model Name APP-51 Function Electronic Hook Switch — remote call answer/end Compatible Phones Polycom SoundPoint IP 320/321/330/331/335/430/450/550/560/650/670; VVX 300/310/400/410/500/600/1500 Compatible Headsets Poly Savi Series, CS500/CS500 XD Series, Voyager Legend CS TAA Compliant Yes