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Sunday, August 8, 2010

Parallel Port (RS 232)


Parport is a driver for the traditional PC parallel port. The port has 17 physical pins and 8 ground pins that make a total of 25 pin. The original parallel port divided those pins into three groups: data, control, and status. The data group consists of 8 output pins, the control group consists of 4 pins, and the status group consists of 5 input pins.
In the early 1990’s, the bidirectional parallel port was introduced, which allows the data group to be used for output or input. The HAL driver supports the bidirectional port, and allows the user to set the data group as either input or output. If configured as output, a port provides a total of 12 outputs and 5 inputs. If configured as input, it provides 4 outputs and 13 inputs.


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