This DB9 manual data switch box can be used to switch between four computers to a peripheral device or one computer to four peripheral devices. Connectors are fully shielded for maximum EMI/RFI protection. Heavy-duty dial contorl switch knob. Anti-skid rubber feet. All lines are switched for total compatibility with all 9-pin connectors supplied. DB9 I/O female x 1 ABCD port male. Switch box does not require power. Cable may be required sold seperately. Standards: UL, CSA, ISO 9001:2000 manufacturer.