This BL-04S+P U10PS-19 Equivalent RJ-45 / PLX QD Cable enables direct connection to most standard telephone system handsets. It allows you to move away from your desk during a call without removing the headset. It also lets you put a call on hold, by simply disconnecting the headset from the QD during a call. Its an ideal solution for intensive telephone users such as in customer care centers and technical support services.