LAN phone system with automatic fallback for power or network failure

• US 6,700,970 B1
• Filed: 07/17/2000
• Issued: 03/02/2004
• Est. Priority Date: 07/17/2000
• Status: Expired due to Fees

• Current Assignee: Aox Incorporated
• Original Assignee: Aox Incorporated
• Inventors: Aronson, Michael, Schmidt, Thomas Joseph
• Primary Examiner(s): BUI, BING Q
• Application Number:
  US09/617,777
• Time in Patent Office: 1,324 Days
• Field of Search: 370/216, 370/217, 379/79, 379/167.13, 379/225, 379/232, 379/307, 379/322, 379/323, 379/395.01, 379/413
• US Class Current: 379/225
• CPC Class Codes: H04L 41/0677 Localisation of faults
• CPC Class Codes: H04M 3/42314 in private branch exchanges
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

In a telephone system employing a PBX server to communicate with local telephones over a local area network, fallback adapters are provided to automatically respond to a power failure and also respond to the failure of the PBX server to automatically connect the telephones directly to a telephone line. This automatic connection enables the telephones to be used as analog phones and make and receive calls directly without using the PBX server. Power failure is detected by relays which default to a position to connect the telephones directly to the telephone line. The fallback detectors have controller logic which detects the presence of a ringing signal on the telephone line and the failure of the PBX to respond to the ringing signal. In addition, the fallback detectors detect the failure of the PBX to respond when a telephone is used to attempt to make an outgoing call or a call to another one of the local telephones. When the controller logic detects a failure of the PBX server to respond, the controller logic actuates the relays to their default positions.

Claims

1. A telephone system comprising a plurality of telephones, a PBX server connected to said telephones and operable to route telephone calls between said telephones and remote telephones over a telephone line via a public switched telephone network, a fallback adapter connected to at least one of said telephones, said fallback adapter comprising a relay device having an active position and a default position, said relay device being connected to an external power source and normally being maintained in said active position when power from said external power source is present and switching to said default position when power from said external power source is not present, said relay device providing a direct current connection between said one of said telephones and said telephone line when said relay device is in said default position, said fallback adapter having an incoming call signal detector to detect the presence of an incoming call signal on said telephone line, and controller logic responsive to the detection of an incoming call signal on said telephone line by said incoming call signal detector followed by a failure of said PBX server to respond to said incoming call signal to cause said relay device to switch to said default position.

2. A telephone system as recited in claim 1, wherein said controller logic is responsive to the failure of said PBX server to respond to one of said telephones going to an off-hook state to cause said relay device to switch to said default position.

3. A telephone system as recited in claim 2, wherein each of said telephones connected to said PBX server has a fallback adapter as recited in claim 2.

4. A telephone system as recited in claim 1, wherein each of said telephones connected to said PBX server has a fallback adapter as recited in claim 1.

5. A telephone system as recited in claim 3, wherein said PBX server and the fallback adapters connected to each of said telephones and the connection between said PBX server and the telephones comprises a local area network, said PBX server routing an incoming telephone call to a selected one of said telephones by means of said local area network.

6. A telephone system as recited in claim 5, wherein said PBX server transmits a message to said fallback adapters acknowledging receipt of an incoming call signal on said telephone line, said controller logic in each of said fallback adapters detecting the failure of said PBX server to transmit said message acknowledging receipt of an incoming call signal to actuate the relay device of the corresponding fallback detector to the default position.

7. A telephone system as recited in claim 6, wherein said PBX server transmits said message acknowledging the receipt of an incoming call signal in AC digitized signals over said telephone lines to said fallback adapters.

8. A telephone system as recited in claim 1, wherein said relay device comprises a relay having said active and default positions and being connected to be energized by said power source to be maintained in said active position when power from said power source is present, said relay having electrical contacts to provide said direct current connections between said one of said telephones and said telephone line when said relay is in said default position.

9. A telephone system as recited in claim 1, wherein said incoming call signal comprises a sequence of rings, said controller logic counting the number of rings in said incoming call signal and when the number of rings in said incoming call reaches a predetermined number causing said relay device to switch to said default position.

10. A telephone system comprising a plurality of telephones, a PBX server connected to said telephones and operable to route telephone calls between said telephones and remote telephones over a telephone line via a public switched telephone network, a fallback adapter connected to at least one of said telephones, said fallback adapter comprising a relay device having an active position and a default position, said relay device providing a direct current connection between said one of said telephones and said telephone line when said relay device is in said default position, said fallback adapter having an incoming call signal detector to detect the presence of an incoming call signal on said telephone line, and controller logic responsive to the detection of an incoming call signal on said telephone line by said incoming call signal detector followed by the failure of said PBX server to respond to said incoming call signal to cause said relay device to switch to said default position.

11. A telephone system as recited in claim 10, wherein said controller logic is responsive to the failure of said PBX server to respond to one of said telephones going to an off-hook state to cause said relay device to switch to said default position.

12. A telephone system comprising a plurality of telephones, a PBX server connected to said telephones and operable to route telephone calls between said telephones and remote telephones over a telephone line via a public switched telephone network, a fallback connector connected to at least one of said telephones, said fallback adapter comprising a relay device having an active position and a default position, a circuit in said fallback adapter detecting when one of said telephones goes off-hook, controller logic in said fallback detector responsive to the detection by said circuit of said one of said telephones going off-hook to transmit a message to said PBX server indicating the change of state of said one of said telephones to an off-hook condition, said PBX server being operable to transmit a second message to said fallback adapter acknowledging receipt by said PBX server of said first message, said controller logic being responsive to the failure of said PBX server to send said second message within a predetermined time interval following the transmission of said first message to said PBX server to cause said relay device to switch to said default position.

13. A telephone system as recited in claim 12, wherein said relay device comprises a relay having said active and default positions and being connected to be energized from an external power source, and is normally held in said active position when power from said external power source is present and switching to said default position when power from said external power source is not present.