Sennheiser RJ9 to USB Cord for Wired Amplifier | Headsets.com
Converter Adapter | Converts RJ-9 to 2.5mm for phones that have a 2.5mm jack., (2200-11095-002) | Use with APP-50, APP-51 EHS for Polycom, Connecting telephone devices to 2.5mm headset mini jack
4P4C RJ9 Cable,3.5mm Smartphone Headset to RJ9 Adapter Cable,Adapter Cable Converter for IP Phones Telephone and for Plantronics
cable rj9 - Connectic Systems
Amazon.com: NEORTX RJ9 to RJ9 Cable 6.5ft, RJ9 Male to RJ9 Male 4P4C Telephone Cord Handset Cord Telephone Handset Coiled Cord Cable Telephone Spiral Cable (White) : Electronics
Amazon.com: NECABLES 2Pack Short RJ9 Cable 1ft 4P4C Phone Cord Telephone Cable RJ9 / RJ10 / RJ22 4P4C Male to Male Straight for Both Data and Voice Black - 1 Foot : Electronics
2 Pack) Black RJ9 4P4C Straight or Reverse Cable. Custom Size From 2" - 10ft | eBay