QD Bottom Coil Cord c with a RJ 9 Plug for connection between headset and desk phone with cable wiring termination R,M-,M+,R on RJ Mod Plug.???? ? East to connect.??? ? Compatible with Most Cisco IP Phone- such as 79xx, Avaya Call Master V, Call Master VI .. etc??? ? Yellow Color Ring (Shrink tube) on cable for easy reference.??? ? RoHs Compliance