Importance

Loading Importance Indicators...

Abstract

A connection system of a public network subscriber and a private network subscriber in ISDN includes a first PBX for connecting the public network subscriber and the public network, a second PBX for the private network subscriber and the private network, and third PBXs for connecting the public line and the private line. The first PBX selects one of the third PBXs as an access point to the private network, and forms a first set-up message having the public line number of the selected access point as a destination, the received private line number as a sub-address, and the public line number of the public network subscriber as a calling party identification. The second PBX selects one of the third PBXs as an access point to the public network, and forms a second set-up message having the private line number of the selected access point as a destination, the received public line number as a sub-address, and the private line number of the private network subscriber as a calling party number. Each of the third PBXs previously stores the identification numbers permitted access to the private network and the public network. Only when the calling party number of the received set-up message is identical to one of the identification numbers, the connection is permitted between the public line and the private line.

Loading the Abstract Image...

First Claim