Combined handset and POTS filter

• US 6,301,337 B1
• Filed: 09/18/1997
• Issued: 10/09/2001
• Est. Priority Date: 09/18/1997
• Status: Expired due to Term

• Current Assignee: Ikanos Communications Incorporated (Qualcomm, Inc.)
• Original Assignee: Globespan Inc.
• Inventors: Scholtz, William H., Muralt, Arnold
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): BARNIE, REXFORD N
• Application Number:
  US08/932,899
• Time in Patent Office: 1,482 Days
• Field of Search: 379/1, 379/5, 379/6, 379/12, 379/21, 379/22, 379/23-30, 379/93.09, 379/164, 379/370, 379/377, 379/93.05, 379/93.06, 379/93.07, 379/90.01, 379/110.01, 379/387, 379/399
• US Class Current: 379/30
• CPC Class Codes: H04M 1/24 Arrangements for testing
• CPC Class Codes: H04M 1/738 Interface circuits for coupling substations to external telephone lines H04M1/78 takes precedence
• CPC Class Codes: H04M 3/2209 for lines also used for data transmission
• CPC Class Codes: H04M 3/308 Craftsperson test terminals

Abstract

The present invention is generally directed to a telephone handset for testing the transmission quality of a local loop. In accordance with one aspect of the invention, the telephone handset includes a connector configured to connect to the local loop at, for example, a junction box. The invention also includes a low-pass filter circuit electrically interposed between the connector and operational circuitry of the telephone handset. In operation, the low-pass filter is designed to pass (substantially undisturbed) electrical signals within the POTS frequency band from the connector to the operational circuitry. In the same way, the low-pass filter is designed to substantially block the passage of electrical signals above the POTS frequency range. In this way, the low-pass filter blocks the introduction of high frequency signals, which may otherwise generate intermodulation products within the audible range, from reaching the operational circuitry of the testing handset. In accordance with another feature of one embodiment of the invention, a device is provided for detecting the presence of xDSL signals on a local loop. In accordance with this embodiment, at least one band-pass or high-pass filter is added in parallel with the low-pass filter. The output of the at least one band-pass or high-pass filter is then analyzed to determine whether an xDSL signal is present within that frequency band (defined by the at least one band-pass or high-pass filter).

Claims

1. An improved telephone for use in a system carrying both POTS and xDSL signal transmissions, comprising:

operational circuitry designed to provide and support operational functions of the telephone;

an input/output connector for communicating signals in a POTS frequency band between a local loop and the operational circuitry;

a plurality of low-pass filter circuits disposed for selective interconnection between the input/output connector and the operational circuitry; and

switching means electrically connected to the input/output connector, each of the plurality of low-pass filter circuits, and the operational circuitry, the switching means adapted to selectively interconnect one of the plurality of low-pass filter circuits between the input/output connector and the operational circuitry.

2. The telephone as defined in claim 1, wherein the switching means includes a double-pole double-throw switch.

3. The telephone as defined in claim 1, wherein the switching means includes a multi-position double-pole rotary switch.