Portable telecommunications test instrument with line condition monitoring

• US 5,157,708 A
• Filed: 10/04/1991
• Issued: 10/20/1992
• Est. Priority Date: 10/04/1991
• Status: Expired due to Fees

• Current Assignee: Michael Kurth
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Garthwaite, John H., Rollins, David M., Stocklin, Clay A.
• Primary Examiner(s): SCHREYER, STAFFORD
• Application Number:
  US07/771,269
• Time in Patent Office: 382 Days
• Field of Search: 379/21, 379/6, 379/27, 379/30, 324/527, 324/539, 324/542, 324/555, 324/556
• US Class Current: 379/21
• CPC Class Codes: H04M 3/308 Craftsperson test terminals

Abstract

A handheld battery-powered telecommunications test instrument for monitoring the status of a pair of wires. A tone-generating circuit generates a tone signal in response to the user manually selecting operation in a tone-generating mode. The instrument monitors the pair of wires to determine whether an on-hook, off-hook or ringing signal is present on the wires, and if present, generates an interrupt control signal through a microprocessor. Logic circuitry connected to the microprocessor results in connecting and disconnecting the tone-generating circuit and the pair of wires to selectively apply the tone signal to the wires. In response to the control signal and the user selecting the tone-generating mode, the microprocessor connects the tone-generation circuit to the pair of wires if no control signal is generated, and disconnects the tone-generating circuit if the control signal is generated. The presence of the on-hook, off-hook and ringing signals on the pair of wires is determined by measuring the voltage between the pair of wires. A menu is generated by the microprocessor from which the user can select the frequency and amplitude for the tone signal.

Claims

1. A portable self-powered telecommunications test instrument for monitoring the status of a pair of wires, the instrument comprising:

a case sized to be held in one hand and containing therein the circuitry of the instrument;

a tone generating circuit for generating a tone signal;

a battery to provide power to said tone generating circuit;

means for the user to manually enable operation of the instrument in a tone generating mode;

means for monitoring the pair of wires to determine whether an on-hook signal, an off-hook signal, or a ringing signal is present on the pair of wires, and if either an on-hook, off-hook, or ringing signal is present on the pair of wires, generating a control signal;

control means for connecting and disconnecting said tone generating circuit and the pair of wires to selectively apply said tone signal to the pair of wires; and

means, responsive to said control signal and the user selecting said tone generating mode using said manual means, for causing said control means to connect said tone generating circuit to the pair of wires if the user selected said tone generating mode and no control signal is generated, and disconnecting said tone generating circuit from the pair of wires if the control signal is generated, whereby the operational mode of the instrument is changed automatically if the pair of wires are in use.

2. The instrument of claim 1 wherein said tone signal is selected from a menu providing a choice of a plurality of tone frequencies and amplitudes.

3. The instrument of claim 1 wherein said monitoring means generates an on-hook indicator signal if an on-hook signal is determined to be present on the pair of wires, an off-hook indicator signal if an off-hook signal is determined to be present on the pair of wires, and a ringing indicator signal if a ringing signal is determined to be present on the pair of wires and the instrument further includes a display to indicate the presence of said on-hook signal indicator, said off-hook signal indicator, or said ringing signal indicator, whereby said display indicates to the user which one of an on-hook signal, an off-hook signal or a ringing signal is present on the pair of wires.

4. The circuit of claim 3 wherein said monitoring means determines the presence of said on-hook, said off-hook and said ringing signals by measuring a voltage between the pair of wires.