4.7 Error Correction
Similar to data compression, modems may be set to do error correction. While there is some overhead cost involved which slows down the byte/sec flow rate, the fact that error correction strips off start and stop bits actually increases the data byte/sec flow rate.
For the serial port's interface with the external world, each 8-bit byte has 2 extra bits added to it: a start-bit and a stop-bit. Without error correction, these extra start and stop bits usually go right thru the modem and out over the phone lines. But when error correction is enabled, these extra bits are stripped off and the 8-bit bytes are put into packets. This is more efficient and results in higher byte/sec flow in spite of the fact that there are a few more bytes added for packet headers and error correction purposes.
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