This DB25 manual data switch box can be used to switch between four different PC computers to one serial/ parallel peripheral device such as printer or one PC computer to switch between four serial/ parallel peripheral devices. Connectors are fully shielded for maximum EMI/RFI protection. Heavy-duty dial contorl switch knob. Anti-skid rubber feet. DB25 25 pin connectors. DB25 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.