Boy those Plantronics EHS cables are confusing! So many different names! Here are their common Plantronics names + our Catalog Numbers. You’re welcome! APC -4 = Cat # 1975 = PLT CS50 EHS for Cisco Phones APC-41 = Cat # 2141 = PLT EHS for Cisco 7900 Series Phones (CS500 and Savi Version)* APC-42 = Cat # 2243 = PLT EHS for Cisco Phones APP-5 = Cat # 1606 = PLT CS50 EHS for Polycom Phones [DISCONTINUED] APP-51 = Cat # 2139 = PLT EHS for Polycom Phones (CS500 and Savi Version) APS-1 = Cat # 1604 = PLT CS50 EHS for Siemens Phones APS-11 = Cat # 2140 = PLT EHS for Aastra & Siemens Phones (CS500 and Savi Version) APT-3 = Cat # 1605 = PLT CS50 EHS for Avaya-Tenovis Phones [DISCONTINUED] APV-6B = Cat # 2136 = PLT CS50 EHS for Avaya 2420, 4600, & 5000 Phones [DISCONTINUED] APV 62 & APV 63 = Cat # 2138 = PLT EHS for Avaya 1400 & 9000 Phones (CS500 and Savi Version) APV 65 = Cat # 2137 = PLT EHS for Avaya 2420, 4600, & 5000 Phones (CS500 and Savi Version)