Method and apparatus for interfacing a cellular fixed wireless terminal to the extension side of a PBX/PABX

• US 6,324,410 B1
• Filed: 09/30/1999
• Issued: 11/27/2001
• Est. Priority Date: 09/30/1999
• Status: Expired due to Fees

• Current Assignee: Telular Corporation (Ametek Incorporated)
• Original Assignee: Telular Corporation (Ametek Incorporated)
• Inventors: Engelking, Frederick, Nathanson, Rex, Giacopelli, Daniel
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US09/408,709
• Time in Patent Office: 789 Days
• Field of Search: 455/554, 455/555, 455/422, 455/524, 455/516, 379/156, 379/355
• US Class Current: 455/554.1
• CPC Class Codes: H04W 88/021 adapted for Wireless Local Loop operation

Abstract

A private branch exchange (PBX/PABX) is provided with a fixed wireless terminal, which allows both incoming and outgoing calls to be made on the private branch exchange. The fixed wireless terminal is coupled to the private branch exchange via an interface unit connected to one of the analog extension lines of the private branch exchange. A telephone extension serviced by the PBX/PABX places a call to a remote cellular telephone, or a remote cellular telephone user places a call to the telephone extension. When the PBX-user makes a call to a remote cellular telephone, one picks up a local PBX/PABX extension, and hears a dial tone, signifying that the PBX/PABX is ready to service his call. The caller then dials the directory number of the PBX/PABX extension which is provided for cellular calls. The PBX/PABX then automatically connects the caller to the cellular extension, which is the interfaced fixed wireless terminal. The caller then dials the directory number of the remote cellular telephone, and waits for connection. When a remote cellular telephone user calls the fixed wireless terminal interfaced to the PBX/PABX, he simply dials the cellular directory number of that fixed wireless terminal in the usual manner. When the fixed wireless terminal answers, the caller will hear the dial tone of the interfaced PBX/PABX, signifying that the PBX/PABX is ready to service his call. The remote caller then dials the extension on the PBX/PABX for the party to whom he wishes to speak, and is then connected.

Claims

1. In a private branch exchange (PBX/PABX) comprising a plurality of analog telephone extensions for connecting a plurality of landline telephone extensions thereto in order to be serviced thereby, the improvement comprising:

A cellular fixed wireless terminal operatively coupled to one of said plurality of analog telephone extensions, said cellular fixed wireless terminal providing central-office functions, such as ring voltage and dial tone for a landline, POTS-type telephone; and

cellular interfacing means for coupling said cellular fixed wireless terminal to said one analog telephone extension;

said cellular fixed wireless terminal comprising a cellular or cellular-like transceiver and cellular interface adapting means for coupling a landline-type telephone instrument to said cellular or cellular-like transceiver, and for providing central-office functions, such as ring voltage and dial tone, for the landline-type telephone instrument;

whereby at least one of an incoming call and an outgoing call may be effected by said cellular fixed wireless terminal via the private branch exchange.

2. The private branch exchange (PBX/PABX) according to claim 1, wherein said interfacing means comprises ring detector means for detecting when one of said fixed wireless terminal and private branch exchange emit ring signals, hook-switch means for causing the said fixed wireless terminal and private branch exchange to go off-hook or on-hook, loop-termination means for terminating a call, loop-current monitoring means for determining that a call is in progress or has ended, and audio-path connection means for providing audio connection between said fixed wireless terminal and said private branch exchange;

and computer means comprising software means for controlling the operation of each said hook switch means, and audio connection means;

said ring detection means and said loop-current monitor means being coupled to said computer means.

3. The private branch exchange (PBX/PABX) according to claim 2, wherein each loop-current monitoring means for monitoring the loop current of said fixed wireless terminal and private branch exchange detects a loop-current interrupt causing the computer means, to thereby disconnect the audio connection between said fixed wireless terminal and said private branch exchange and place both said hook-switch means in the on-hook condition to cause the fixed wireless terminal and PBX/PABX to reset to an initial condition of waiting for ring signals.

4. The private branch exchange (PBX/PABX) according to claim 1, wherein said interfacing means comprises two circuit paths, one for said fixed wireless terminal, and one for said private branch exchange, and computer means for controlling the functioning of said two circuit paths.

5. The private branch exchange (PBX/PABX) according to claim 4, wherein each of said two circuit paths comprises:

ring detector means for detecting when the respective said fixed wireless terminal and private branch exchange emit ring signals, hook-switch means for causing the respective said fixed wireless terminal and private branch exchange to go off-hook or on-hook, loop-termination means for providing AC and DC impedance for terminating a call, loop-current monitoring means for determining that a call is in progress or has ended, and audio-path connection means for providing audio connection between said fixed wireless terminal and said private branch exchange;

said computer means comprising software means for controlling the operation of each hook-switch means, and audio connection means;

said ring-detector means and said loop-current monitor means being coupled to said computer means.

6. The private branch exchange (PBX/PABX) according to claim 4, wherein each of said two circuit paths further comprises loop-current monitor means for monitoring the loop current of the respective fixed wireless terminal and private branch exchange for determining when a call is in progress or has ended, whereby upon the call being ended, a respective said loop-current monitor means detects a loop-current interrupt, causing the computer means to thereby disconnect the audio connection between said fixed wireless terminal and said private branch exchange, and place both said hook switch means in the on-hook condition to cause said fixed wireless terminal and PBX/PABX to reset to an initial condition of waiting for ring signals.

7. A method of making a cellular call using a private branch exchange (PBX/PABX), which private branch exchange comprises a plurality of analog extensions to which are connected telephone-extensions serviced by the private branch exchange, comprising:

(a) initiating an outgoing cellular call via one of said plurality of analog extensions by said one telephone-extension;

(b) said step (a) comprising instructing the private branch exchange that the call to be placed is a cellular call to be made over a cellular radio network;

(c) connecting said one telephone-extension to a fixed wireless terminal coupled to another one of said plurality of extensions of the private branch exchange which fixed wireless terminal provides central-office functions such as ring voltage and dial tone when said one telephone extension is coupled thereto;

(d) dialing a telephone number on said one telephone-extension; and

(e) connecting said one telephone-extension to the telephone called via said fixed wireless terminal.

8. The method of making a cellular call using a private branch exchange according to claim 7, wherein said step (b) comprises dialing on said one telephone-extension a code that the private branch exchange recognizes as a command to connect said one telephone-extension to said fixed wireless terminal.

9. The method of making a cellular call using a private branch exchange according to claim 7, wherein said step (c) comprises coupling said one telephone-extension to said fixed wireless terminal by means of an interfacing unit that couples the fixed wireless terminal to an analog telephone extension line of said private branch exchange.

10. The method of making a cellular call using a private branch exchange according to claim 7, further comprising:

(f) terminating the call upon one of the said telephone-extension and the called telephone hanging up.

11. The method of making a cellular call using a private branch exchange according to claim 7, further comprising:

(f) receiving an incoming cellular call on said fixed wireless terminal;

(g) connecting the incoming call from the fixed wireless terminal to the private branch exchange via said another extension thereof;

(h) directing the call to the called PBX/PABX telephone-extension.

12. A method of adapting a private branch exchange (PBX/PABX) for making or receiving a cellular telephone call via a cellular wireless network, which private branch exchange comprises a plurality of analog extensions for connecting a plurality of telephone-extensions thereto in order to be serviced thereby, comprising:

(a) operatively coupling an interfacing means for interfacing a fixed wireless terminal to a private branch exchange to one of said plurality of analog extensions;

(b) connecting a fixed wireless terminal to said interfacing means for providing central-office functions, such as ring voltage and dial tone, to said plurality of telephone -extensions;

(c) said step (b) establishing a bi-directional audio path between the fixed wireless terminal and the private branch exchange, whereby at least one of an incoming call on the fixed wireless terminal may be connected to the private branch exchange, and an outgoing call made by the private branch exchange may be placed over a cellular network via the fixed wireless terminal.