PBX equipment with dial signal modification
Automatic route selection of a private telephone network path on the basis of a public telephone network number
Exchange system for incoming calls from direct-in lines
Private network with means for establishing virtual tie trunks between PBXS through ISDN public network
Direct dialing-in method in a pabx
Virtual private network connecting system Patent #: 5339356
ApplicationNo. 195083 filed on 02/14/1994
US Classes:379/229, Interexchange signalling379/196, At switching center379/198, PBX379/220.01, With interexchange network routing379/225Multi-PBX interconnection
ExaminersPrimary: Dwyer, James L.
Assistant: Dharia, Parag
Attorney, Agent or Firm
Foreign Patent References
International ClassH04M 003/54
Foreign Application Priority Data1993-02-12 JP
AbstractA 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.