Apparatus and method for detecting and powering an accessory

• US 6,038,457 A
• Filed: 12/05/1997
• Issued: 03/14/2000
• Est. Priority Date: 12/05/1997
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Barkat, Shakil
• Primary Examiner(s): Tsang, Fan S.
• Assistant Examiner(s): Jackson, Blane J.
• Application Number:
  US08/985,988
• Time in Patent Office: 830 Days
• Field of Search: 455/572, 455/556, 455/557, 455/571, 455/90, 455/127, 455/350, 320/15, 320/34, 320/54, 320/39
• US Class Current: 455/556.1
• CPC Class Codes: H04B 1/3877 Arrangements for enabling portable transceivers to be used in a fixed position, e.g. cradles or boosters
• CPC Class Codes: H04M 1/6058 involving the use of a headset accessory device connected to the portable telephone
• CPC Class Codes: H04M 1/72409 by interfacing with external accessories hands-free H04M1/60

Abstract

A radiotelephone (100) is coupled to accessory (200) by way of a novel interface provided by connector (190). Accessory (200) is a headset including a microphone (220) and a speaker (230) that may be plugged into a jack in radiotelephone (100) and worn by the user. Accessory (300) provides an RS-233 serial interface for communicating information between radiotelephone (100) and a personal computer (400). Controller (130) of radiotelephone (100) detects the presence of a 10K ohm resistor (202) to determine that accessory (200) is coupled to connector (190), and the presence of a 22K ohm resistor (202) to determine that accessory (300) is coupled to connector (190). When accessories (200) and (300) are detected, a liner regulator (116) is swathed on by controller to provide a 2.7V voltage source for powering accessories (200) and (300).

Claims

1. Interface apparatus for coupling a radiotelephone to one of a first and second accessories having respective first and second predetermined impedances, the first and second predetermined impedances having respective first and second values, said interface apparatus comprising:

an analog to digital converter for detecting the value of the first and second predetermined impedances;

a switch for coupling a power source to the accessory in response to a control signal;

a controller having a memory storing the first and second values and being coupled to the analog to digital converter for comparing the detected value to the stored first and second values and generating the control signal when the detected value is substantially the same as one of the stored first and second values;

and first and second bypass capacitors disposed on the first and second accessories, respectively, and being coupled to the switch.

2. Interface apparatus for coupling a radiotelephone to one of a first and second accessories having respective first and second predetermined impedances, the first and second predetermined impedances having respective first and second values, said interface apparatus comprising:

an analog to digital converter for detecting the value of the first and second predetermined impedances;

a switch for coupling a power source to the accessory in response to a control signal;

a controller having a memory storing the first and second values and being coupled to the analog to digital converter for comparing the detected value to the stored first and second values and generating the control signal when the detected value is substantially the same as one of the stored first and second values; and

wherein said first accessory further includes a data device for encoding and decoding information signals, said interface apparatus further comprising;

a data bus coupled to the data device; and

said controller further being coupled to the data bus for transmitting and receiving information signals to and from, respectively, the data device when the detected value is substantially the same as the stored first value.

3. Interface apparatus for coupling a radiotelephone to one of a first and second accessories having respective first and second predetermined impedances, the first and second predetermined impedances having respective first and second values, said interface apparatus comprising:

an analog to digital converter for detecting the value of the first and second predetermined impedances;

a switch for coupling a power source to the accessory in response to a control signal;

a controller having a memory storing the first and second values and being coupled to the analog to digital converter for comparing the detected value to the stored first and second values and generating the control signal when the detected value is substantially the same as one of the stored first and second values; and

wherein said second accessory further includes audio amplifying circuitry coupled to a microphone and a speaker, said interface apparatus further comprising;

a speaker audio bus coupled to the audio amplifying circuitry;

a microphone audio bus coupled to the audio amplifying circuitry; and

said switch coupling the power source to the audio amplifying circuitry in response to the control signal.

4. A radiotelephone adapted to be coupled to an accessory having a predetermined impedance and audio amplifying circuitry coupled to a microphone and a speaker, said radiotelephone comprising:

a receiver operable on cellular radio channels for receiving information signals;

a transmitter operable on cellular radio channels for transmitting information signals; and

a controller coupled to the receiver and the transmitter for communicating information signals, and further coupled to the accessory for detecting the predetermined impedance and switching a power source to the audio amplifying circuitry in response to detection of the predetermined impedance.

5. The radiotelephone according to claim 4 further including a bypass capacitor disposed on the accessory and being coupled to the power source.

6. Interface apparatus for coupling a radiotelephone to an accessory having a predetermined impedance, the predetermined impedance having a value, said interface apparatus comprising:

an analog to digital converter for detecting the value of the predetermined impedance;

a switch for coupling a power source to the accessory in response to a control signal;

a controller having a memory storing the value and being coupled to the analog to digital converter for comparing the detected value to the stored value and generating the control signal when the detected value is substantially the same as the stored value; and

a bypass capacitor disposed on the accessory and being coupled to the switch.

7. Interface apparatus for coupling a radiotelephone to an accessory having a predetermined impedance, the predetermined impedance having a value, said interface apparatus comprising:

an analog to digital converter for detecting the value of the predetermined impedance;

a switch for coupling a power source to the accessory in response to a control signal;

a controller having a memory storing the value and being coupled to the analog to digital converter for comparing the detected value to the stored value and generating the control signal when the detected value is substantially the same as the stored value; and

wherein said accessory further includes a data device for encoding and decoding information signals, said interface apparatus further comprising;

a data bus coupled to the data device; and

said controller further being coupled to the data bus for transmitting and receiving information signals to and from, respectively, the data device when the detected value is substantially the same as the stored value.

8. Interface apparatus for coupling a radiotelephone to an accessory having a predetermined impedance, the predetermined impedance having a value, said interface apparatus comprising:

an analog to digital converter for detecting the value of the predetermined impedance;

a switch for coupling a power source to the accessory in response to a control signal;

a controller having a memory storing the value and being coupled to the analog to digital converter for comparing the detected value to the stored value and generating the control signal when the detected value is substantially the same as the stored value; and

wherein said accessory further includes audio amplifying circuitry coupled to a microphone and a speaker, said interface apparatus further comprising;

a speaker audio bus coupled to the audio amplifying circuitry;

a microphone audio bus coupled to the audio amplifying circuitry; and

said switch coupling the power source to the audio amplifying circuitry in response to the control signal.

9. A method of interfacing a radiotelephone to an accessory having predetermined impedance and audio amplifying circuitry coupled to a microphone and a speaker, the predetermined impedance having a value, said method comprising the steps:

detecting the value of the predetermined impedance;

comparing the detected value to a stored value and generating a control signal when the detected value is substantially the same as the stored value; and

switching a power source to the audio amplifying circuitry in response to the control signal.