Method and apparatus for interfacing telephone apparatus to a digital, analog or hybrid telephone switching system

• US 7,031,454 B1
• Filed: 02/29/2000
• Issued: 04/18/2006
• Est. Priority Date: 11/06/1997
• Status: Expired due to Fees

• Current Assignee: GN Netcom Incorporated (GN Store Nord A/S)
• Original Assignee: Hello Direct Incorporated (Synergy Communications Management)
• Inventors: Stelman, Bruce W.
• Primary Examiner(s): Tran, Sinh
• Assistant Examiner(s): Briney, III, Walter F
• Application Number:
  US09/515,589
• Time in Patent Office: 2,240 Days
• Field of Search: 379/387, 379/26.07, 379/244, 379/9.06, 379/75.07, 379/473.02, 379/246, 379/243, 379/388, 379/390, 379/399, 379/93.05, 379/387.01, 379/387.02, 379/399.01, 370/252
• US Class Current: 379/387.01
• CPC Class Codes: H04M 1/738 Interface circuits for coupling substations to external telephone lines H04M1/78 takes precedence

Abstract

An adaptive interface method and apparatus for interfacing a telephony appliance such as an analog telephone, modem, fax modem, facsimile machine teleconferencing device, headset, VoIP telephone or non-compatible digital telephone to a digital, analog or hybrid telephone system, such as a private branch exchange (PBX). The interface device is suitable for use with a variety of PBX'"'"'s produced by different manufacturers, despite differences in signaling characteristics between the PBX and an associated PBX-compatible telephone. The interface device is coupled between A telephony appliance and a PBX. In order to communicate the interface device “learns” the characteristics of the telephony appliance and also of the PBX. This is accomplished by: determining whether each component of the telephone system is an analog or digital device; and, if the telephone system is a digital, monitoring communications between the PBX and the PBX-compatible telephone. Then, the interface device is configured according to each appropriate protocol by retrieving set of operational parameters from a plurality of such sets pre-stored in a memory device within the interface device. The learning technique allows the interface device to automatically adapt itself to variations in signaling characteristics between the PBX and PBX-compatible telephone sets among the different PBX manufacturers.

Claims

1. An interface apparatus for interfacing a telephony appliance to a telephone switching system, the interface apparatus comprising:

a. a signal path through the apparatus for communicating signals between the telephony appliance and the telephone switching system;

b. means for identifying a first communication protocol utilized by the telephony appliance from among a plurality of communication protocols and for configuring the signal path according to the first communication protocol, wherein configuring the signal path includes dynamically programming a control circuit within the signal path according to the identified first communication protocol; and

c. means for identifying a second communication protocol utilized by the telephone switching system from among the plurality of communication protocols and for configuring the signal path according to the second communication protocol, wherein configuring the signal path according to the second communication protocol includes programming the control circuit according to conversion parameters associated with the identified second communication protocol, further wherein the first communication protocol and the second communication protocol must first be identified before the telephony appliance and the telephone switching system begin communicating with one another.

2. The interface device according to claim 1 wherein the signal path includes a converter for converting the digital samples into an analog signal.

3. The interface device according to claim 1 wherein the signal path is utilized for communicating voice and control signals between the telephony appliance and the telephone switching system.

4. The interface device according to claim 3 comprising a circuit for detecting an on-hook/off-hook condition of the telephony appliance and for providing a notification to the telephone switching system in response to a change in the on-hook/off-hook condition of the telephony appliance.

5. A method of interfacing a telephony appliance to a telephone switching system, the method comprising steps of:

a. providing a signal path for communicating signals between the telephony appliance and the telephone switching system;

b. identifying a first communication protocol utilized by the telephony appliance from among a plurality of communication protocols;

c. identifying a second communication protocol utilized by the telephone switching system from among the plurality of communication protocols, wherein the first communication protocol and the second communication protocol must first be identified before the telephony appliance and the telephone switching system begin communicating with one another; and

d. configuring the signal path according to the protocol utilized by the telephony appliance and according to the protocol utilized by the telephone switching system, wherein configuring the signal path includes dynamically programming a control circuit within the signal path according to the identified first communication protocol and according to conversion parameters associated with the identified second communication protocol.

6. The method according to claim 5 wherein the signal path includes a converter for converting digital voice samples into an analog signal.

7. The method according to claim 5 wherein the signal path is utilized for communicating voice and control signals between the telephony appliance and the telephone switching system.

8. The method according to claim 7 further comprising a step of detecting an on-hook/off-hook condition of the telephony appliance.

9. The method according to claim 8 further comprising a step of providing an indication of the on-hook/off-hook condition of the telephony appliance to the telephone switching system via the signal path in response to the telephony appliance changing from an on-hook condition to an off-hook condition.

10. The method according to claim 8 further comprising a step of providing an indication of the on-hook/off-hook condition of the telephony appliance to the telephone switching system via the signal path in response to the telephony appliance changing from an off-hook condition to an on-hook condition.

11. A method of interfacing a telephony appliance to a telephone switching system, the method comprising steps of:

a. determining whether the telephone switching system communicates voice signals as digital samples or as analog signals;

b. determining whether the telephony appliance communicates voice signals as digital samples or as analog signals;

c. activating a first signal path when the telephone system communicates voice signals as digital samples, the first signal path for communicating the voice signals between the telephony appliance and the telephone switching system wherein the first signal path includes a converter for converting the digital samples into an analog signal;

d. activating a second signal path when the telephone system communicates voice signals in analog format, the second signal path for communicating the voice signals between the telephony appliance and the telephone switching system wherein the second signal path includes analog signal processing circuits;

e. identifying a first communication protocol utilized by the telephone switching system, wherein the identified first communication protocol includes associated conversion parameters which are used to dynamically program a first control circuit within the first signal path or a second control circuit within the second signal path such that the programmed first control circuit or the programmed second control circuit translates the voice signals passed between the telephone switching system and the telephony appliance; and

f. identifying a second communication protocol utilized by the telephony appliance, wherein the first communication protocol and the second communication protocol must first be identified before the telephony appliance and the telephone switching system begin communicating with one another.

12. The method according to claim 11 further comprising a step of adapting an active one of the first and second signal paths according to requirements of the telephone switching system.

13. The method according to claim 11 further comprising a step of adapting the second signal path according to requirements of the telephone switching system wherein the step of adapting comprises a step of adjusting an amplification level according to a level of a dial tone provided by the telephone switching system.

14. The method according to claim 11 wherein the step of determining whether the telephone switching system communicates voice signals includes a step of measuring a first voltage supplied by the telephone switching system to a resistive load.

15. The method according to claim 14 wherein the step of determining whether the telephone switching system communicates voice signals further comprises a step of measuring a second voltage supplied by the telephone switching system under unloaded conditions.

16. The method according to claim 15 wherein the step of determining whether the telephone switching system communicates voice signals further comprises a step of comparing a ratio of the first and second voltages to a range of expected ratios.

17. The method according to claim 11 further comprising a step of detecting an on-hook/off-hook condition of the telephony appliance.

18. The method according to claim 17 further comprising a step of providing an indication of the on-hook/off-hook condition of the telephony appliance to the telephone switching system in accordance with the identified protocol in response to the telephony appliance changing from an on-hook condition to an off-hook condition.

19. The method according to claim 17 further comprising a step of providing an indication of the on-hook/off-hook condition of the telephony appliance to the telephone switching system in accordance with the identified protocol in response to the telephony appliance changing from an off-hook condition to an on-hook condition.

20. A method of interfacing a telephony appliance to a telephone switching system, the method comprising steps of:

a. determining a first communication protocol of the telephone switching system;

b. determining a second communication protocol of the telephony appliance, wherein the first communication protocol and the second communication protocol must first be identified before the telephony appliance and the telephone switching system begin communicating with one another;

c dynamically programming a control circuit according to conversion parameters associated with the determined first communication protocol; and

d. translating a communication according to the first communication protocol of the telephone switching system using the programmed control circuit and further according to the second communication protocol of the telephony appliance.