Secure cordless telephone extension system and method

• US 5,911,119 A
• Filed: 10/15/1996
• Issued: 06/08/1999
• Est. Priority Date: 03/22/1993
• Status: Expired due to Term

• Current Assignee: Low Environ AG LLC (Intellectual Ventures LLC)
• Original Assignee: Phonex Broadband Corp.
• Inventors: Knab, John M., Bartholomew, David B., Bullock, Scott R.
• Primary Examiner(s): Wolfe, Willis R.
• Assistant Examiner(s): Vo, Hieu T.
• Application Number:
  US08/729,876
• Time in Patent Office: 966 Days
• Field of Search: 455/462, 455/402, 455/410, 455/425, 455/465, 455/422, 455/561, 455/560, 455/566, 455/415
• US Class Current: 455/402
• CPC Class Codes: H04B 2203/5441 Wireless systems or telephone
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04M 1/725 Cordless telephones user interfaces specially adapted therefor H04M1/724

Abstract

A method and system for multiple access telephone communications is described. The system utilizes one or more base units connected to subscriber lines, and multiple extension units in communication with each base unit via building power lines. Secure multiple access coding is used to prevent eavesdropping and interference. Extension units may employ cordless telephone technology. Caller ID information transmitted with incoming telephone signals may be transmitted to extension units via building power lines and displayed on the extension handset or cradle.

Claims

1. A telephone communications system for transmitting and receiving telephone communications via AC power lines in a building, the system comprising:

a) a base unit and an extension unit, each said unit comprising;

i) off hook circuitry for detecting off hook status in the extension unit;

ii) means for converting analog telephone communications signals to digital data signals;

iii) means for generating a transmission carrier;

iv) code division multiple access transmitter means for modulating said transmission carrier by said digital data signals;

v) at least one additional multiple access means for further modulating and controlling transmission and reception of said modulated transmission carrier, said additional multiple access means being selected from the group consisting of;

1) time division multiple access multiplexing means for controlling the times at which the digital data signals are transmitted and received;

and

2) frequency division multiple access means for changing said transmission carrier'"'"'s frequency;

vi) means for coupling said modulated transmission carrier to the power lines of the building;

vii) code division multiple access receiving means for demodulating said modulated transmission carrier received via said power lines to produce analog telephone communications signals;

b) means for coupling at least one subscriber telephone line to said base unit;

c) ring detect circuitry associated with said base unit for detecting a ring signals in said subscriber line and transmitting a ring signal via said power lines in said building to the extension unit;

d) ring generator circuitry associated with said extension unit for detecting a ring signal transmitted via said power lines and generating a ring signal in said extension unit;

e) caller identification detect circuitry associated with said base unit for detecting caller identification signals transmitted with said ring signal and transmitting a caller identification signal via said power lines in said building to said extension unit;

f) caller identification circuitry associated with said extension unit for detecting said caller identification signal transmitted via said power lines; and

g) a display device on said extension unit on which caller identification information is presented to the telephone subscriber.

2. A telephone communications system in accordance with claim 1, wherein said extension unit comprises a cradle and a cordless handset;

wherein said ring signals, telephone communications signals, and caller identification signals are transmitted from said cradle to said cordless handset as radio frequency signals; and

wherein said display device is located on said cordless handset.

3. A cordless multiple access telephone communications system for transmitting and receiving telephone communications via AC power lines in a building, the system comprising:

a) a base unit and an extension unit, each said unit comprising;

i) off hook circuitry for detecting off hook status in the extension unit;

ii) means for converting analog telephone communications signals to digital data signals;

iii) means for generating a transmission carrier;

iv) code division multiple access transmitter means for modulating said transmission carrier by said digital data signals;

v) at least one additional multiple access means for further modulating and controlling transmission and reception of said modulated transmission carrier, said additional multiple access means being selected from the group consisting of;

1) time division multiple access multiplexing means for controlling the times at which the digital data signals are transmitted and received; and

2) frequency division multiple access means for changing said transmission carrier'"'"'s frequency;

vi) means for coupling said modulated transmission carrier to the power lines of the building;

vii) code division multiple access receiving means for demodulating said modulated transmission carrier received via said power lines to produce analog telephone communications signals;

b) a cordless handset associated with said extension unit;

c) RF transmission circuitry in said extension unit for transmitting said analog telephone communications signals to said cordless handset; and

d) RF reception circuitry in said handset for receiving said analog telephone communication signals transmitted from said extension unit.

4. A method for telephone communications, the method comprising the steps of:

a) converting analog telephone communication signals to digital communication signals;

b) producing a transmission carrier;

c) modulating said transmission carrier with said digital communication signals using code division multiple access techniques;

d) further modulating and controlling said transmission carrier by at least one additional multiple access technique selected from the group consisting of;

i) time division multiple access for controlling the times at which the transmission carrier is transmitted and received; and

ii) frequency division multiple access for changing said transmission carrier'"'"'s frequency to another frequency;

e) coupling said modulated transmission carrier to power lines of a building;

f) receiving and demodulating said modulated transmission carrier transmitted via said power lines using code division multiple access receiving techniques to produce analog communication signals;

g) converting said analog communication signals to RF signals;

h) transmitting said RF signals; and

i) receiving said RF signals in a cordless telephone handset.

5. A method for telephone communications, the method comprising the steps of:

a) detecting a first ring signal;

b) detecting a caller identification signal transmitted after said first ring signal and before a second ring signal;

c) converting said first and second ring signals and all subsequent ring signals to digital ring signals;

d) converting said caller identification signal to a digital caller identification signal;

e) converting analog voice signals to digital voice signals;

f) producing a transmission carrier;

g) modulating said transmission carrier with said digital ring, caller identification, and voice signals using code division multiple access techniques;

h) further modulating and controlling said transmission carrier by at least one additional multiple access technique selected from the group consisting of;

i) time division multiple access for controlling the times at which the transmission carrier is transmitted and received; and

ii) frequency division multiple access for changing said transmission carrier'"'"'s frequency to another frequency;

i) coupling said modulated transmission carrier to power lines of a building;

j) receiving and demodulating said modulated transmission carrier transmitted via said power lines using code division multiple access receiving techniques to produce analog ring, caller ID, and voice signals.

6. A method in accordance with claim 5, comprising the further steps of:

k) converting said ring, caller ID and voice signals to RF signals;

l) transmitting said RF signals from an extension unit cradle; and

m) receiving said RF signals in a cordless telephone handset;

wherein caller ID information contained in said caller ID signal is displayed on said cordless telephone handset.