Sunday, September 17, 2006

Experimenters and the Demise of the Serial Port

The common RS232 serial port was once ubiquitous on any laptop or desktop PC manufactured. Many PCs came standard with not one but two of these ports. We used them to attach modems and sometimes printers to the computer systems. Often Ham Radio operators and other electronics experimenters used the power of the PC and the readily available serial port to create inexpensive or unique gadgets by individually controlling the pins of a serial port. Items like data aquisition systems, EPROM or microcontroller programers, machine controls, etc. were created.

The serial port has vanished or is quickly vanishing from the PC of 2006 and beyond. Few commercial peripherals require a serial port and most newer devices use Ethernet or the now common USB port as their interface. What about all those cool gadgets we have lying around our shops and work benches?

Perhaps we need a new type of USB to Serial adapter targeted at "non-traditional" applications. The adapter would interface to the PC via a USB port but the hardware side would have a small microcontroller and level converters that truly reproduced the voltage levels and input/outputs of the traditional 9-pin serial port. On the PC side of things a software driver would be needed to look for all the world like a standard COM port down to the register levels needed to twiddle individual pins on the port. That bit twiddling would be transparently passed back and forth via USB to the micro and level converters on the other end of the converter. The end result is that it could function as a normal serial port but low level programs like programmers and other control devices could also read and write individual pins on the nine pin port.