Cordless telephone

• US 5,915,227 A
• Filed: 07/21/1998
• Issued: 06/22/1999
• Est. Priority Date: 08/04/1995
• Status: Expired due to Term

• Current Assignee: Uniden Corporation (Cornwall Capital Management LP)
• Original Assignee: Uniden Corporation (Cornwall Capital Management LP)
• Inventors: Ishida, Hiroyuki, Takahashi, Kunihiro, Fujino, Masayasu, Hikuma, Hideo, Ishida, Yuzo, Otsuji, Katsuhiko
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Nguyen, Lee
• Application Number:
  US09/119,648
• Time in Patent Office: 336 Days
• Field of Search: 455/566, 455/38.4, 455/426, 455/462, 455/463, 455/465, 455/550, 455/554, 455/555, 455/564, 455/565
• US Class Current: 455/566
• CPC Class Codes: H04M 1/72505 Radio link set-up procedures
• CPC Class Codes: H04M 1/72508 using a control channel

Abstract

A cordless telephone consisting of base and handset units is disclosed wherein a control circuit incorporated in the base unit comprises first and second D/A converters, first and second A/D converters, and first and second sync. signal generation circuits. The first and second D/A converters respectively convert digital signals from the handset unit and a PBX. The first and second A/D converters convert the analog signals provided from the first and second D/A converters to transmit them to the PBX and handset unit, respectively. The first sync. signal generation circuit regenerates a first clock signal synchronously with a sync. signal provided from the PBX to render the first A/D and second D/A converters to operate in synchronism with the sync. signal from the PBX. The second sync. signal generation circuit generates a second clock signal which is independent of the sync. signal from the PBX to render the first D/A and second A/D converters to operate in synchronism with the second clock signal. Accordingly, the synchronization between the base and handset units is effected independently of the synchronization signal from the PBX.

Claims

1. A cordless telephone consisting of a base unit connected to a PBX and a handset unit which wirelessly transmits or receives signals to or from said base unit, comprising:

a buffer memory incorporated in said handset unit, for storing a key code which is correspondingly generated when a dial key is depressed;

key code transmission control means incorporated in said handset unit, for transmitting the generated key code to said base unit via a transmitter of said handset unit;

acknowledge transmission means incorporated in said base unit, for generating and transmitting an acknowledge signal to said handset unit when the key code transmitted from said handset unit is received at said base unit;

display means incorporated in said handset unit; and

display control means incorporated in said handset unit, for controlling to display the number of the dial key on said display means by reading out the key code from said buffer memory when said handset unit receives the acknowledge signal from said acknowledge transmission means, thereby a dial-key-echo-back signal from said PBX being not required to be transmitted to said handset unit.

2. A method of displaying numbers of dialed keys on a display of a handset unit of a cordless telephone, comprising the steps of:

(a) generating a key code when a dial key is depressed at said handset unit;

(b) storing the key code in a buffer memory incorporated in said handset unit;

(c) transmitting the generated key code from said handset unit to a base unit of said cordless telephone via a transmitter of said handset unit;

(d) generating an acknowledge signal at said base unit and transmitting it to said handset unit when the key code transmitted from said handset unit is received at said base unit;

(e) reading out the key code from said buffer memory and displaying the dial key number associated with the read out key code on the display when said handset unit receives the acknowledge signal; and

(f) repeating the steps (a)-(e) until the depression of dial keys is finished, thereby a dial-key-echo-back signal from said PBX being not required to be transmitted to said handset unit, in order to display the numbers of the dialed keys.