PURPOSE: To increase the apparent line accommodating capability by constituting a network control program so that a scan limit value and an address replacement value from one operating mode to the other operating mode.

CONSTITUTION: A communication processor incorporates a network control program NCP, two lines of 4,800bps, one line of 48kbps and one line of 2,400bps are accommodated. Two lines of 4,800bps and one line of 2,400bps are used at the operation at daytime with a terminal equipment and in changing it into the night operation using two lines of 4,800bps and one line of 48kbps, the operator gives a command to change the pattern from the daytime operating pattern into the night operating pattern if an LZ interruption from the line of 2,400bps does not come for 1min to change the scan limit value and the address replacement value.