Method and apparatus to protect fixed wireless terminal from foreign voltage at the tip and ring connection

• US 6,615,056 B1
• Filed: 10/01/1999
• Issued: 09/02/2003
• Est. Priority Date: 06/03/1999
• Status: Expired due to Term

• Current Assignee: Telular Corporation (Ametek Incorporated)
• Original Assignee: Telular Corporation (Ametek Incorporated)
• Inventors: Engelking, Fred, Schornack, Louis, Taylor, Alvin, Giacopelli, Daniel
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US09/409,891
• Time in Patent Office: 1,432 Days
• Field of Search: 455/554, 455/74.1, 379/557, 379/33
• US Class Current: 455/554.1
• CPC Class Codes: H04M 1/715 using two or more extensions per line cordless telephones H04M1/725
• CPC Class Codes: H04M 1/725 Cordless telephones user interfaces specially adapted therefor H04M1/724

Abstract

A method and apparatus for preventing harmful foreign voltage from being applied to a fixed wireless terminal. Upon the detection of a harmful voltage, the fixed wireless terminal is prevented from being connected to the tip-and-ring lines of a premises'"'"' land-line. The voltage is detected by a voltage-detector. The invention may also be used to disconnect the normally-closed connection of the fixed wireless terminal with the tip-and-ring lines of the premises'"'"' land-line upon the detection of a harmful voltage on the tip-and-ring lines.

Claims

1. In an fixed wireless terminal for connecting a telephone means to a public switched telephone network, said fixed wireless terminal having a telephone-jack means for connecting a telephone means thereto, and a microprocessor for controlling the operation thereof, the improvement comprising:

means for preventing harmful land-line voltages from being connected to said fixed wireless terminal when said telephone-jack means is directly connected to premises'"'"' tip and ring lines of a public switched telephone network.

2. The fixed wireless terminal of claim 1, wherein said means for preventing comprises a prevention means controlled by said microprocessor for disconnecting the fixed wireless terminal from a land-line voltage, and voltage-detection means operatively coupled with said microprocessor.

3. The fixed wireless terminal of claim 2, wherein said prevention means comprises switch means, said switch means being normally open to disconnect the fixed wireless terminal from a harmful land-line voltage.

4. The fixed wireless terminal of claim 2, wherein said microprocessor comprises memory means, said memory means storing software for controlling said prevention means and for communication from said voltage-detection means;

said voltage-detection means, upon sensing a foreign voltage on the tip-and-ring lines of a PSTN land-line providing a signal to said microprocessor, whereby said software sends a signal to said prevention means for placing said prevention means in an open, disconnect-state.

5. The fixed wireless terminal of claim 2, wherein said voltage detection means is periodically operated to check for foreign voltages on the premises'"'"' tip-and-ring lines;

said microprocessor periodically sending a signal to said switch means to close said switch when said voltage detection means has been activated for sensing foreign voltages, in order to isolate the fixed wireless terminal from the premises'"'"' tip-and-ring lines.

6. The fixed wireless terminal of claim 4, wherein said voltage detection means is periodically operated to check for foreign voltages on the premises′

tip-and-ring lines;

said microprocessor periodically sending a signal to said switch means to open said switch means when said voltage detection means has been activated for sensing foreign voltages, in order to isolate the fixed wireless terminal from the premises′

tip-and-ring lines.

7. The fixed wireless terminal of claim 5, whereby said microprocessor is operatively coupled to said voltage-detection means and said switch means, whereby upon said voltage-detection means sending a signal to said microprocessor, said microprocessor causes said switch means to open.

8. A method of preventing land-line voltages from being connected to a fixed wireless terminal, which fixed wireless terminal comprises a microprocessor, comprising:

(a) detecting the presence of a voltage on a premises'"'"' ring-and-tip lines of a PSTN;

(b) sending a signal to the microprocessor indicating the presence of voltage on the tip-and-ring lines;

(c) preventing the connection between the fixed wireless terminal and the tip-and-ring lines of a PSTN.

9. The method of preventing land-line voltages from being connected to a fixed wireless terminal, according to claim 8, wherein said step (c) is performed by said microprocessor.

10. The method of preventing land-line voltages from being connected to a fixed wireless terminal, according to claim 8, wherein said step (c) comprises keeping a switch in a normally-open state, whereby accidental connection of a wireless fixed terminal to premises tip-and-ring lines is prevented.

11. The method of preventing land-line voltages from being connected to a fixed wireless terminal according to claim 8, wherein said step (c) comprises opening a normally-closed switch, whereby, a fixed wireless terminal that is utilizing premises tip-and-rings lines is disconnected therefrom.

12. The method of preventing land-line voltages from being connected to a fixed wireless terminal according to claim 8, wherein said step (c) is performed when the microprocessor no longer senses a call on the fixed wireless terminal.

13. The method of preventing land-line voltages from being connected to a fixed wireless terminal according to claim 8, wherein said step (b) is performed when a threshold voltage is detected.