Private branch exchange having a central control unit and a mobile control unit subordinate thereto

• US 5,544,226 A
• Filed: 09/11/1995
• Issued: 08/06/1996
• Est. Priority Date: 08/30/1991
• Status: Expired due to Fees

• Current Assignee: Alcatel NV (Nokia Corporation), Alcatel SA (Nokia Corporation)
• Original Assignee: Alcatel NV (Nokia Corporation)
• Inventors: Schulz, Manfred, Bezler, Monika, Weis, Bernd, Turban, Karl-Albert, Siegmund, Gerd
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Chernoff, Michael B.
• Application Number:
  US08/526,354
• Time in Patent Office: 330 Days
• Field of Search: 379/58, 379/59, 379/60, 379/61, 379/63, 379/242, 379/243, 379/244, 379/90, 379/92, 379/93, 379/62, 370/60.1, 370/94.1, 370/94.2, 370/110.1
• US Class Current: 455/555
• CPC Class Codes: H04W 84/16 WPBX [Wireless Private Branch Exchange]

Abstract

A private branch exchange (PABX) with an integrated mobile part for controlling cordless terminals (HS) is established, which can be operated from base stations (BS).

The private branch exchange (PABX) contains freely configurable interface modules (I/F) for wired (DE) and cordless (HS) terminals, which can be operated from a base station (BS). A central control unit (PABX-CPU) is provided to control all call handling and service feature control tasks, and a subordinate control unit (Mobile-CPU) for call setup and switch-off control of the cordless terminals (HS) in accordance with a set of assigned call numbers. The control units (PABX-CPU, Mobile-CPU) and the interface modules (I/F) are connected with each other through a bus system (BUS).

Claims

1. A private branch exchange (PABX) comprising:

a plurality of interface modules (I/F) configured for connecting a plurality of corded terminals (DE) by wire and for connecting at least one base station (BS) which serves a radio cell (FZ) and is connectable via an air interface to a plurality of cordless terminals (HS);

a central control unit (PABX CPU) for processing all call handling in the private branch exchange for the plurality of corded terminals (DE), including processing corded terminal call-setup and call-cleardown messages and corded terminal connection orders, and for further processing only a part of the call handling for the plurality of cordless terminals (HS) in response to a mobile control message signal, including processing all cordless terminal connection orders in a same manner as corded terminal connection orders, but not processing cordless terminal call-setup and call-cleardown messages;

a mobile control unit (mobile CPU) subordinate to the central control unit (PABX CPU) for processing all cordless terminal call-setup and call-cleardown messages for a predetermined set of call numbers assigned to the plurality of cordless terminals (HS), and for providing the mobile control message signal to the central control unit (PABX CPU); and

a bus system (BUS) to which are connected the central control unit (PABX CPU), the mobile control unit (mobile CPU), and the interface modules (I/F) for exchanging control messages and executing switching tasks.

2. A private branch exchange as claimed in claim 1, wherein each of the plurality of interface modules (I/F) is an ISDN S₀ interface module (I/F) (ISDN=Integrated Services Digital Network) for connecting said at least one base station (BS) to make all ISDN service features available to the cordless terminals (HS) via the base station.

3. A private branch exchange as claimed in claim 2 wherein the base station (BS) connected to the ISDN S₀ interface module performs an ISDN-DECT protocol conversion (ISDN=Integrated Services Digital Network, DECT=Digital European Cordless Telephone), so that the cordless terminals (HS) connectable to the base station via the air interface are operable in accordance with DECT protocols.

4. A private branch exchange as claimed in claim 1, wherein the subordinate control unit (mobile CPU) controls an associated terminal identification in accordance with the predetermined set of call numbers, so that only authorized cordless terminals (HS) can set up calls via the base station (BS).

5. A private branch exchange as claimed in claim 4, wherein each of a given number of call numbers of the set of call numbers is assigned to only a single cordless terminal (HS) for identifying a special authorization.

6. A private branch exchange as claimed in claim 4, wherein given call numbers of the set of call numbers are assigned to two or more cordless terminals (HS).

7. A private branch exchange as claimed in claim 6, wherein the mobile control unit (mobile CPU) contains for each base station (BS) connected via an interface module (I/F) one set of call numbers each assigned to one of the cordless terminals of a radio cell, so that in response to a broadcast message from the mobile control unit (mobile CPU) to all base stations (BS) within ranges of radio cells of the private branch exchange, each cordless terminal (HS) can be reached via a roaming terminal identification.

8. A private branch exchange as claimed in claim 7, wherein, when a given cordless terminal (HS) is leaving one radio cell and entering another, in response to a request from the given cordless terminal (HS), the mobile control unit (mobile CPU) can switch an existing connection with the given cordless terminal (HS) to another base station (BS) associated with another radio cell.

9. A private branch exchange as claimed in claim 5, wherein the mobile control unit (mobile CPU) contains for each base station (BS) connected via an interface module (I/F) one set of call numbers each assigned to one of the cordless terminals (HS) of a radio cell, so that in response to a broadcast message from the mobile control unit (mobile CPU) to all base stations (BS) within ranges of radio cells of the private branch exchange, each cordless terminal (HS) can be reached via a roaming terminal identification.

10. A private branch exchange as claimed in claim 4, wherein the mobile control unit (mobile CPU) contains for each base station (BS) connected via an interface module (I/F) one set of call numbers each assigned to one of the cordless terminals (HS) of a radio cell, so that in response to a broadcast message from the mobile control unit (mobile CPU) to all base stations (BS) within ranges of radio cells of the private branch exchange, each cordless terminal (HS) can be reached via a roaming terminal identification.

11. A private branch exchange as claimed in claim 6, wherein, when a given cordless terminal (HS) is leaving one radio cell and entering another, in response to a request from the given cordless terminal (HS), the mobile control unit (mobile CPU) can switch an existing connection with the given cordless terminal (HS) to another base station (BS) associated with another radio cell.

12. A private branch exchange as claimed in claim 5, wherein, when a given cordless terminal (HS) is leaving one radio cell and entering another, in response to a request from the given cordless terminal (HS), the mobile control unit (mobile CPU) can switch an existing connection with the given cordless terminal (HS) to another base station (BS) associated with another radio cell.

13. A private branch exchange as claimed in claim 4, wherein, when a given cordless terminal (HS) is leaving one radio cell and entering another, in response to a request from the given cordless terminal (HS), the mobile control unit (mobile CPU) can switch an existing connection with the given cordless terminal (HS) to another base station (BS) associated with another radio cell.