US 7,577,135 B2
IP telephone system
Hiroyuki Sato, Fukushima-ken (Japan); Shinji Saitou, Fukushima-ken (Japan); Tadashi Saitou, Koriyama (Japan); Takahiro Sasaki, Fukushima-ken (Japan); Fumio Urayama, Fukishima-ken (Japan); Hiroshi Endo, Fukushima-ken (Japan); Tatsuya Yoshida, Fukushima-ken (Japan); Shinsuke Isono, Fukushima-ken (Japan); Kaoru Mashiko, Fukushima-ken (Japan); Takahiro Abe, Fukushima-ken (Japan); and Kazuhiko Kubo, Fukushima-ken (Japan)
Assigned to Hitachi Communication Technologies, Ltd., Tokyo (Japan)
Filed on Mar. 09, 2006, as Appl. No. 11/371,227.
Claims priority of application No. 2005-067515 (JP), filed on Mar. 10, 2005; application No. 2005-067633 (JP), filed on Mar. 10, 2005; application No. 2005-067709 (JP), filed on Mar. 10, 2005; application No. 2005-067816 (JP), filed on Mar. 10, 2005; application No. 2005-067940 (JP), filed on Mar. 10, 2005; and application No. 2005-068101 (JP), filed on Mar. 10, 2005.
Prior Publication US 2006/0217997 A1, Sep. 28, 2006
Int. Cl. H04L 12/50 (2006.01); H04Q 11/00 (2006.01)
U.S. Cl. 370—386 9 Claims
OG exemplary drawing
 
1. An IP telephone system configured by a main control device for controlling the entire operation of an IP exchange; said IP exchange storing a plurality of IP terminals for each lodgment through a circuit by a control of said main control device and comprising a plurality of signal control devices performing a call control; said circuit for connecting between said IP exchange and said lodgment; a backup exchange installed in said lodgment for detecting a trouble of said IP exchange or a fault of said circuit and backing up said lodgment; and said plurality of lodgments comprising said plurality of IP terminals, said IP telephone system performing a centralized control and operation of all the IP terminals by the IP exchange, wherein said backup exchange performs an access confirmation with said IP exchange, and in a case in which the access confirmation cannot be secured from said IP exchange, determines it as an occurrence of a fault of said IP exchange or a failure of said circuit, and switches over from a waiting state to an operating state; said IP exchange performs an access confirmation with said IP terminals installed in said plurality of lodgments; said plurality of IP terminals, in a case in which a life check based on the access confirmation from said IP exchange cannot be received, log in to said backup exchange after logging out from said IP exchange; said backup exchange performs communication control of said IP terminal which is logged in said backup exchange.