This is the Plantronics U10 Cisco Cable that connect any Plantronics H series headset with most Cisco 6900, 7800, 7900, 8900, 9900 series IP phone (as long as it has a RJ-9 headset jack)

It's also used as a replacement cord that connects Plantronics Call Center Headsets to the Plantronics M12, M22, MX10, M10 amplifier. The black coiled cord has a QuickDisconnect (QD) plug on one end and a male modular plug on the other end. part# 26716-01

Key Features:

• 10' coiled cord
• Replacement cable for for use with Plantronics Call Center headsets (H-Series) and direct connect to Plantronics M12, Plantronics MX10, Plantronics M22
• old part# 26716-01
   

Direct connect cable for Cisco IP phone models (not all listed):

• Cisco IP 6921, 6941, 6945, 6961
• Cisco IP 7931G, 7940, 7940G, 7941, 7941G, 7942G, 7945, 7945G
• Cisco IP 7960, 7960G, 7961, 7961G, 7965G
• Cisco IP 7970, 7970G, 7971G, 7975G
• Cisco IP 8811, 8841, 8845, 8851, 8861, 8865
• Cisco IP 8941, 8945, 8961, 9951, 9971

If you have the Cisco SPA modesl (303, 501G, 502G, 504G, 508G, 509G or 525G, 921, 922, 941, 942, 962, 921, 922, 941, 942), you need the Plantronics Cisco SPA Cable

Old Poly part # 26716-01

New HP part # 85R38AA