EXTENSION TELEPHONE SYSTEM, MAIN DEVICE, WIRELESS TELEPHONE TERMINAL, COMPUTER READABLE PROGRAM, AND COMMUNICATION METHOD OF EXTENSION TELEPHONE SYSTEM

摘要

PROBLEM TO BE SOLVED: To receive an extension telephone service provided by a main device by a wireless telephone terminal regardless of whether the main device and the wireless telephone terminal are in the same network.;SOLUTION: A wireless telephone terminal 2 sends, to a push notification server 3, a push notification request with a notification destination as a main device 1 and a notification content as a call control message to send a call control message to the main device 1 and receives, from the push notification server 3, a push notification with a notification destination as the main device 1 and a notification content as a call control message to receive the call control message from the main device 1. The main device 1 receives, from the push notification server 3, a push notification with a notification source as the wireless telephone terminal 2 and a notification content a call control message to receive the call control message from the wireless telephone terminal 2, and sends, to the push notification server 3, a push notification request with a notification destination as the wireless telephone terminal 2 and a notification content as a call control message to send the call control message to the wireless telephone terminal 2.;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2019,JPO&INPIT