PURPOSE: To execute exchange and connection by using a virtual call number identifying a calling terminal equipment when plural terminal equipments call to a call terminal equipment by a virtual call number in a system connecting the plural equipments to one line with an exchange network.

CONSTITUTION: TA1 calls by dialing the virtual incoming call number b1 of TB7. At this time, an exchange 51 receives the call processing with the virtual incoming call number b1 as an incoming call number and a call line number A as a call number. The exchange 51 recognizes that the incoming call number (virtual incoming call number b1) is a virtual number, retrieves a correspondence table to convert the call incoming number from the number b1 to the incoming call line number B and convert the calling number from the calling line number A to the virtual call number a1 and, after then, incoming call processes to TB7. TB7 can recognize the incoming call is from TA1 by a display showing that the call number is the virtual call number a1.