Hands-free device for use with a cellular telephone in a car to permit hands-free operation of the cellular telephone

• US 5,802,167 A
• Filed: 11/12/1996
• Issued: 09/01/1998
• Est. Priority Date: 11/12/1996
• Status: Expired due to Fees

• Current Assignee: Chu-Chai Hong
• Original Assignee: Chu-Chai Hong
• Inventors: Hong, Chu-Chai
• Primary Examiner(s): Zele, Krista
• Assistant Examiner(s): WEAVER, SCOTT LOUIS
• Application Number:
  US08/745,493
• Time in Patent Office: 658 Days
• Field of Search: 379/387, 379/388, 379/390, 379/395, 379/413, 379/419, 379/420, 379/428, 379/429, 379/432, 379/434, 379/440, 379/441, 379/442, 379/443, 455/90, 455/126, 455/127, 455/128, 455/569, 455/571, 455/572, 455/573, 455/575
• US Class Current: 379/388.02
• CPC Class Codes: H04M 1/6075 adapted for handsfree use in a vehicle H04M1/6058 takes precedence; arrangements for holding telephones in a vehicle B60R11/0241
• CPC Class Codes: H04M 19/08 with current supply sources at the substations generating ringing current H04M19/04

Abstract

A hands-free device is adapted for use with a cellular telephone in a car to permit hands-free operation of the cellular telephone, and includes a main terminal, a secondary terminal, and a microphone provided on one of the main and secondary terminals. The main terminal includes a first casing, a power supplying unit, a voltage regulating circuit, a first connector, an audio output amplifier circuit, and a sound output unit. The secondary terminal includes a second casing, a second connector connected removably to the first connector, a third connector connected removably to the cellular telephone, a hands-free control circuit, a voltage output control circuit, and a gain control circuit. The secondary terminal can be replaced so that the hands-free device can be used with any type of cellular telephone without changing the main terminal.

Claims

1. A hands-free device adapted for use with a cellular telephone in a car to permit hands-free operation of the cellular telephone, said hands-free device comprising:

a main terminal including;

a first casing;

a power supplying unit provided on said first casing and adapted to be connected electrically to a power source of the car;

a voltage regulating circuit disposed in said first casing and connected electrically to said power supplying unit so as to generate a stable voltage signal therefrom;

a first connector provided on said first casing and connected electrically to said voltage regulating circuit so as to receive said voltage signal therefrom;

an audio output amplifier circuit disposed in said first casing and connected electrically to said voltage regulating circuit so as to receive said voltage signal therefrom, said audio output amplifier circuit being further connected electrically to said first connector for amplifying an audio signal received by said first connector; and

a sound output unit connected electrically to said audio output amplifier circuit for reproducing said audio signal from said audio output amplifier circuit;

a secondary terminal including;

a second casing;

a second connector provided on said second casing and connected removably to said first connector;

a third connector provided on said second casing and adapted to connect removably with the cellular telephone;

a hands-free control circuit disposed in said second casing and connected electrically to said third connector, said hands-free control circuit being adapted to control hands-free operation of the cellular telephone;

a voltage output control circuit disposed in said second casing and connected electrically to said second and third connectors, said voltage output control circuit adjusting said voltage signal received by said first connector from said voltage regulating circuit and being adapted to provide said voltage signal to the cellular telephone via said third connector; and

a gain control circuit disposed in said second casing and connected electrically to said second and third connectors, said gain control circuit being adapted to adjust level of said audio signal received from the cellular telephone via said third connector prior to supplying said audio signal to said audio output amplifier circuit via said first and second connectors; and

a microphone provided on one of said main terminal and said secondary terminal for picking up voice signals to be supplied to the cellular telephone by said secondary terminal.

2. The hands-free device as claimed in claim 1, wherein said microphone is provided on said main terminal, said main terminal further including a microphone amplifier circuit disposed in said first casing and connected electrically to said voltage regulating circuit so as to receive said voltage signal therefrom, said microphone amplifier circuit being further connected electrically to said first connector and to said microphone so as to amplify said voice signals picked up by said microphone and being adapted to provide said voice signals to the cellular telephone via said first, second and third connectors.

3. The hands-free device as claimed in claim 2, wherein said microphone is an external microphone.

4. The hands-free device as claimed in claim 1, wherein said power supplying unit is formed as a plug which is adapted to be inserted into a lighter socket of the car.

5. The hands-free device as claimed in claim 4, wherein said power supplying unit extends directly from said first casing.

6. The hands-free device as claimed in claim 4, wherein said main terminal further includes a cable which couples electrically said power supplying unit to said voltage regulating circuit in said first casing.

7. The hands-free device as claimed in claim 1, wherein said first connector includes a connecting plug on one end of an elastic cord, said second connector including a connecting socket formed on said second casing for engaging removably said connecting plug of said first connector.

8. The hands-free device as claimed in claim 1, wherein said third connector includes a connecting plug on one end of a flexible cord that extends from said second casing.

9. The hands-free device as claimed in claim 1, wherein said sound output unit includes a loudspeaker built into said first casing.

10. The hands-free device as claimed in claim 1, wherein said sound output unit is disposed externally of said first casing.

11. The hands-free device as claimed in claim 1, wherein said microphone is built into said second casing of said secondary terminal and is connected electrically to said second connector so as to be adapted to provide said voice signals picked up thereby to the cellular telephone via said second and third connectors.