Black Box Explains... Basic Printer Switches.
Mechanical—A mechanical switch is operated by a knob or by push buttons and uses a set of copper or gold-plated copper contacts to make a connection. The internal resistance created by this type of connection will affect your signals transmission distance and must be taken into account when calculating cable lengths.
Electronic—Although electronic switches are controlled by knobs and pushbuttons like mechanical switches, the switching is accomplished with electronic gates not mechanical contacts. Electronic switches dont have the internal resistance of a mechanical switch—some even have the ability to drive signals for longer distances. And since they dont generate electronic spikes like mechanical switches, theyre safe for sensitive components such as HP® laser printers. Some electronic switches can be operated remotely.