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US 6,038,457 AGranted
Apparatus and method for detecting and powering an accessory
AssigneeMotorola, Inc.
InventorShakil Barkat
Life of this patent
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AssigneeMotorola, Inc.
InventorShakil Barkat
Estimating the term…
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).
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:
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:
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:
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:
Interface apparatus for coupling a radiotelephone to an accessory having a predetermined impedance, the predetermined impedance having a value, said interface apparatus comprising:
Interface apparatus for coupling a radiotelephone to an accessory having a predetermined impedance, the predetermined impedance having a value, said interface apparatus comprising:
Interface apparatus for coupling a radiotelephone to an accessory having a predetermined impedance, the predetermined impedance having a value, said interface apparatus comprising:
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:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Portable telephones adapted for handsfree use: involving the use of a headset accessory device connected to the portable telephone
Portable transceivers: arrangements for enabling portable transceivers to be used in a fixed position, e.g. cradles or boosters
With means for local support of applications that increase the functionality: by interfacing with external accessories
Telephonic communication
Term ended 5 Dec 2017 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention is generally related to radiotelephones, and more particularly to an apparatus and method for detecting and powering a headset accessory for cellular radiotelephones.
Conventional portable cellular radiotelephones may be coupled to a variety of accessories including different size batteries as illustrated in U.S. Pat. Nos. 5,164,652 and 5,237,257, an auxiliary battery as illustrated in U.S. Pat. No. 5,684,384, an external power adapter as illustrated in U.S. Pat. No. 5,506,490, a power booster as illustrated in U.S. Pat. No. 4,636,741, and a headset. The presence of the foregoing accessories may be determined by detecting resistors of a predetermined value or by detecting an electrical signal ground or predetermined voltage on an input signal. Many of these accessories are mounted in a vehicle where they can be powered from the vehicle's battery. However, when a vehicular power source is not available, there is a need for powering an accessory directly from a radiotelephone.
FIG. 1 is a block diagram of a cellular radiotelephone 100 and a headset accessory 200.
FIG. 2 is a block diagram of a data cable accessory 300.
Referring to FIG. 1, there is illustrated a block diagram of a cellular radiotelephone 100 and headset accessory 200, embodying the present invention. In the preferred embodiment, radiotelephone 100 is a cellular telephone such as those manufactured by and available from Motorola, Inc. Radiotelephone 100 is coupled to accessory 200 by way of an 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 in a manner similar conventional stereo headphones. Accessory 200 enables to user to privately listen and speak during a radiotelephone call. Other accessories including but not limited to a handsfree accessory and a desktop charger accessory may be coupled to radiotelephone 100 by way of the interface provided by connector 190.
Radiotelephone 100 includes a radio frequency (RF) receiver 110 a RF transmitter, a controller 130, a microphone 140, a speaker 150, a keyboard 160 for entering information, a display 170 for visually displaying information and status, and interface circuitry coupled to controller 130 for producing interface signals on the accessory interface provided by connector 190. Controller 190 is a conventional microcomputer system that includes a microprocessor device, a non-volatile memory device with a stored program, a volatile memory device for storing data, and an interface device for producing output control signals and receiving input control signals.
Accessory 200 includes predetermined impedance 202, which in the preferred embodiment is a resistor having a predetermined value to indicate that accessory 200 is a headset. Impedance 202 has a value of 10K ohms for the headset accessory 200. Accessory 200 also includes capacitor 208 coupled to the SCI-TX/POWER bus for providing voltage source V1 to headset accessory 200 and its audio amplifying circuitry 220-226 and 230-238. Voltage source V1 is coupled to amplifier 226, amplifier 238, and resistors 208 and 210 which act as a divider for providing voltage source Vref at capacitor 212 and resistor 232. Accessory 200 also includes capacitor 222 coupled to speaker audio bus of connector 190 for capacitvely coupling speaker audio signals to audio amplifier 226 by way of gain setting resistors 224 and 225. Amplifier 226 amplifies the speaker audio signals and couples them to speaker 220. Accessory 200 further includes microphone 230 for providing microphone audio signals. Microphone 230 is coupled by resistor 232 and capacitor 234 to audio amplifier 238 by way of gain setting resistors 236 and 237. Amplifier 238 amplifies the microphone audio signals and couples them to the speaker audio bus of connector 190.