PURPOSE: To improve the service to an extension by starting a call before a set time when morning calls of a number exceeding the capability of simultaneous calling are set in the same time zone.

CONSTITUTION: Counters (CNT) 8 are 288 sets of counters corresponding to the call time zone at an interval of 5min from 00:00 to 23:55, and each counter is incremented by 1 when a morning call is set by the command of a morning call control section (MCC) 3 and decremented by 1 in calling an extension. Succeedingly, the simultaneous call number is set to "3" in advance. When it requires 3min to call all extensions reserving morning call at a time coincident to the present time (e.g., 00:00), although the present time is 00:03, the MCC3 checks the count value of the time zone 00:05 of the CNT8 and it is compared with the set simultaneous call number. If the count value is, e.g., "6", since it exceeds the simultaneous call number "3", the MCC3 applies call processing sequentially the extension for reservation at 00:05 from 00:03.