This RJ11 manual data switch box can be used to switch between four different telephone / phone-type devices. Connectors are fully shielded for maximum EMI/RFI protection. Heavy-duty dial contorl switch knob. Anti-skid rubber feet. RJ11 11 pin connectors. RJ11 I/O female x 1 + ABCD port female. Switch box does not require power. Cable may be required sold seperately. Standards: UL, CSA, ISO 9001:2000 manufacturer.