The Serial pedal is the same overall design as the USB model, but the lead is terminated in a 9-pin serial plug (female).
It contains the same three switches - a large centre area (play/pause for transcription), and one smaller switch at each side (rewind and fast forward.)
Serial foot pedals can be used for transcription on older computers without USB ports, or on PC’s with an operating system including Windows 98 and before.
They can also be used to control programs or processes on a PC, using off-the-shelf or custom-written software.
For instance, pressing one of the buttons could open a new file, open a new customer record, close a record, call a phone number in a record, almost anything you like, depending on how your software has been written to include the foot pedal signals.