## Physical Device Driver Reference

[prev][next][parent][TOC]

### PRT_SETCOMMMODE (52h) - Remarks

The set parallel port communication mode IOCtl informs the parallel port device driver of the communication protocol to use for data transfers. The default communication mode is to use compatible mode.

When compatible mode is set, the forward channel communication protocol is an 8-bit host to peripheral protocol; the reverse channel communication protocol is not supported.

When nibble mode is set, the forward channel communication protocol is compatible mode; the reverse channel communication protocol is a 4-bit peripheral to host protocol.

When byte mode is set, the forward channel communication protocol is compatible mode; the reverse channel communication protocol is an 8-bit peripheral to host protocol.

More information on the communication modes can be found in the IEEE-1284 specification.