JPH11177480A - Mobile communication terminal and adaptor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce effects of noise with a simple configuration by executing optical communication of information with an adaptor device through an optical interface. SOLUTION: An optical interface is constituted by permitting respective light-emitting parts 176 and 656 and light-receiving parts 472 and 652 of a portable equipment main body 400 and a car kit 601 to be installed adjacent to each other to attain an optical communication-enable state. Voice from a microphone 370 is supplied to the light-emitting part 656 as a specified serial/digital signal through an A/D converter 640, a voice processing part 630, a control part 610 and a serial I/F part and is E/0-converted. An E/0-converted optical signal is converted into an electric signal at the light-receiving part 472, then changed to voice data after specified processings through a serial I/F part 456 and a control part 450, encoded and compressed in a B, B processing part 440, modulated in a radio transmitting part and irradiated from an external antenna 395 via a coaxial cable 500 and a interface 603. Thus, voltage conversion between the interfaces is not required and also becomes unlikely to be affected by engine noises.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication terminal and an adapter device suitable for using a mobile communication terminal such as a portable telephone in a car or the like.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show a conventional portable telephone and a car kit for changing the operating environment of the portable telephone by connecting the portable telephone.

[0003] In FIG. 3, a coaxial cable 200 having a curl portion 200A with a connector 201 attached to a mobile phone 100, a speaker 360, and a microphone 37 are provided.
0, a vehicle battery 325, an external antenna 395,
The car kit 99 is constituted by the control unit 300 for connecting all of them.

[0004] As shown in FIG. 2, the configuration of the cellular phone 100 is composed of an SW 116 for selecting an interface section 170 or an antenna 111 provided on a bottom surface 100 A of the cellular phone 100 and connecting to an Dup 112,
B. wireless transmission / reception units 115 and 113 connected to B. B
(Baseband) processing unit 120 and the B.B. B processing unit 1
A receiver 122 and a microphone 124 connected to
And a control unit 130 including a CPU, a ROM, a RAM, and the like.
And Key 14 for key input to the control unit 130
0, a display unit 150 for displaying data output from the control unit 130, the interface unit 170, Amplifier 1 for transmitting and receiving analog signals between B processing units 120
A data bus 12 for transmitting and receiving data signals between the control unit 130 and the interface unit 170;
3 and a power supply unit 160 that supplies power supplied from the battery 190 or the interface unit 170 loaded in the mobile phone 100 to each circuit in the mobile phone 100.

[0005] The control unit 300 includes a reception and transmission power amplifiers 389 and 390 connected to an external antenna 395 and power supplied from the vehicle battery 325 to each circuit and interface in the control unit 300. A power supply section 320 for supplying the power to the section 310, a control section 330 connected to the interface section 310 via the data bus 331, and an HF (Hands Free) section 350 connected to the speaker 360 and the microphone 370.
10 comprises a variable amplifier 341 and an amplifier 342.

[0006] The interface section 310 is connected to the interface section 170 via the coaxial cable 200.

[0007] According to the car kit 99, a mobile phone can be used through the microphone 370 and the speaker 360 in a hands-free manner, that is, without holding the mobile phone 100 by hand.

[0008]

However, in the above car kit 99, since voice information is transmitted by an electric signal via the coaxial cable 200, if the logic levels of the portable telephone 100 and the control unit 300 do not match, voltage conversion is performed. And the structure of the interface part becomes complicated.

Further, a potential difference of the analog ground is generated between the control unit 300 and the mobile phone 100, and it is difficult to reduce engine noise peculiar to a vehicle.

Further, in connection with the form of the coaxial cable 200 and the connector 201, the connector 201 has a multi-core structure, which makes it difficult to reduce the size and cost of the device.
The use of a curl cord as the coaxial cable 200 causes a waveform distortion in an audio signal to be transmitted, thereby hindering a high-speed communication, and a connector 201 for connecting a signal line.
, Static noise is mixed. And this measure is difficult, and there is a problem that a special part is required.

[0011]

According to a first aspect of the present invention, there is provided a mobile communication terminal having an interface for changing an operation environment by connecting to an adapter device. The portion for information transmission is a first optical interface for performing optical communication with the adapter device.

Further, in the second invention, in an adapter device provided with an interface for changing an operation environment of the mobile communication terminal by connecting the mobile communication terminal, at least information transmission for information transmission among the interfaces is provided. Is a second optical interface for performing optical communication with the mobile communication terminal.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) First Embodiment The following is an example in which a mobile communication terminal according to the present invention is applied to a mobile phone and an adapter device is applied to a car kit used by being attached to an automobile. One embodiment will be described.

(A-1) Configuration of First Embodiment FIGS. 1 and 4 show a portable telephone 400 according to the present embodiment.
2 shows a configuration of a car kit 601.

In FIG. 4 showing the appearance, the cellular phone 4
Coaxial cable 5 with connector 501 attached to 00
00, a speaker 360, a microphone 370, an in-vehicle battery 325, an external antenna 395, and a car kit 99 including all of them and a holder 600 having a holding portion 600A for holding the mobile phone 400. ing. The coaxial cable 500
Has no curl portion.

The speaker 360 and the microphone 370
Since the vehicle battery 325 and the external antenna 395 are the same as those of the car kit 99 in FIG. 3, the same reference numerals are given and the detailed description is omitted.

In FIG. 1 showing the internal configuration, an antenna 411 attached to a portable telephone 400 is connected to SW4.
16 are connected. The SW 416 can be connected to an external antenna 395 via a terminal 417, and the external antenna 395 or the antenna 411 can be selectively connected to the Dup 412.
Connect to

Dup 412 is a band-pass filter for separating the transmitting side and the receiving side, and is connected to the radio receiving section 420 and the radio transmitting section 430. This wireless receiving section 420
Is a part for demodulating extracting a low frequency information signal from a high frequency signal, and the radio transmitting unit 430 is a part for performing modulation for putting a low frequency information signal on a high frequency carrier.

In order to transmit a low-frequency information signal obtained by demodulation, the radio receiving unit 420 B (baseband) processing section 440. On the contrary, the radio transmission section 430 receives the low frequency information signal to be put on the carrier wave. It is connected to the B processing unit 440.

This B. The B processing unit 440 encodes and decodes data necessary for a protocol with the base station and compresses and expands audio, and also encodes and decodes audio. In addition to the receiver 442 and the microphone 444, the B processing unit 440 , And a control unit 450.

The control unit 450 includes a CPU, ROM, RA
M, etc., which controls each circuit in the mobile phone 400, and is connected to a Key 452 including a plurality of operation keys for a user, a display unit 454 that displays various information by a liquid crystal or the like, and the like. I have.

A serial I / F unit 456 that enables transmission and reception of serial data between an external device such as a car kit 601 and the control unit 450 is incorporated in the control unit 450. Signal lines 479 and 475 drawn from the serial I / F unit 456 are connected to the amplifier 47, respectively.
8,474.

An amplifier 478 for supplying sufficient power to drive the light emitting section 476 disposed on the bottom section 400A of the portable telephone 400 has an input terminal connected to the signal line 47.
9 is connected. Light receiving unit 4 adjacent to light emitting unit 476
The output terminal of the amplifier 474 having a part of the waveform shaping function in addition to the voltage amplification of the waveform input from the terminal 72 is connected to the signal line 475.

That is, the signal lines 477 and 473 drawn from the amplifiers 478 and 474 are connected to the light emitting unit 476 and the light receiving unit 472, respectively.

The light emitting section 476 and the light receiving section 472
Is provided on the bottom surface portion 400A of the mobile phone 400 and forms an optical interface on the mobile phone 400 side.

The SW 480 connected to the power supply terminal of the amplifier 478 switches the power supply of the amplifier 478 for driving the light emitting section 476 between an external power supply (such as the power supply section 620) and the power supply section 460 as necessary. It is provided for.

The SW 480 is provided mainly for personal computers and digital AV equipment, and is provided for the case where optical communication such as IrDA (infrared data communication) is performed. Even when the distance between the light receiving unit 472 and the light emitting unit 476 of the mobile phone 400 is long, by obtaining sufficient power from the external power source, the light emission can be performed without worrying about the remaining power of the battery 190 loaded in the mobile phone 400. This is to increase the light emission intensity of the unit 476 so as to cope with the situation.

Therefore, normally, the power supply unit 460 built in the mobile phone 400 converts the power of the battery 190 loaded in the mobile phone 400 into a voltage corresponding to each circuit, and converts the power into each circuit in the mobile phone 400. However, when the connector 501 is attached to the mobile phone 400, the Key4
The control unit 450 switches the switching signal line 451 in accordance with the operation of the
Switch SW480 to the power supply unit 620 side, and
0 can be suppressed. Further, in response to the switching of the power supply unit, the signal line 453 for changing the amplification degree is set.
Thus, the amplification degree of the amplifier 478 can be changed.

Terminals 418 and 419 for connecting the power supply 620 on the holder 600 to the SW 480 and the power supply 460 are provided on the bottom 400A.
The three terminals A 417 to 419 are connected to the interface unit 603 by attaching the connector 501 to the mobile phone 400.

The SWs 480 and 416, the radio transmitting unit 430, the radio receiving unit 420, B processing unit 440,
Amplifiers 474 and 478, power supply section 460, signal line 47
9, 475, etc. are all provided on the substrate 401.

On the other hand, inside the holder 600 which is a main part of the car kit 601, the Dup 696 connected to the external antenna 395 and the transmitting and receiving power amplifiers 6
A power amplifying unit 690 is composed of 91 and 692 and Dup 695 connected to Dup 696 via these power amplifiers 691 and 692.

Further, in addition to each circuit in the holder 600,
When selected, the output terminal of the power supply unit 620 that converts the power of the on-board BATT 325 into a required voltage and supplies the power to the mobile phone 400 also has the interface unit 603.
It is connected to the.

The light receiving section 652, the light emitting section 656, the serial I / F section 650, and the amplifiers 654 and 658 provided on the holder 600 correspond to the light receiving section 472, the light emitting section 476, and the serial I / F section of the portable telephone 400, respectively. 45
6, has the same function as the amplifiers 474 and 478, and has the same connection relationship.

The control section 610 connected to the serial I / F section 650 has a control function for all circuits in the holder 600, and is connected to the audio processing section 630 via the data bus 612. Note that the control unit 610 may have an echo canceling function and a noise canceling function for reducing noise peculiar to a vehicle.

The A / D (D) connected to the audio processing unit 630
/ A) The converter 640 performs mutual conversion between an analog signal and a digital signal between the microphone 370 and the speaker 360 and the audio processing unit 630.

The power amplification section 690 and the power supply section 62
0, serial I / F section 650, control section 610, A / D
The (D / A) converter 640 and the like are all
It is provided on.

The serial I / F unit 650 and the control unit 6
Although the audio processing unit 10 and the audio processing unit 630 are separately illustrated in FIG. 1, all of them may be provided in a single-chip DSP (digital signal processor).

The operation of the first embodiment having such a configuration will be described below.

(A-2) Operation of the First Embodiment Each part of the car kit 601 is attached to an automobile in advance. Usually, at the time of this attachment, the external antenna 395 is provided with the outer surface of the vehicle body, and the microphone 370 and the speaker 360 are used by the driver or the like in a hands-free manner for the portable telephone 400.
Is used to select a desired position in the vehicle that is easy to interact with. The holder 600 is attached near the driver's seat in the vehicle so that the mobile phone 400 can be easily attached to and detached from the holding portion 600A.

In this state, the connector 501 is connected to the portable telephone 4
00, the terminal 41 of the bottom portion 400A
7 is connected to the power amplification section 690, and the terminals 418 and 419 are connected to the power supply section 620, respectively.

Then, the portable telephone 400 is placed in the holder 600.
The light emitting unit 476 comes close to the light receiving unit 652, the light receiving unit 472 comes close to the light emitting unit 656, and optical communication can be performed between the mobile phone 400 and the car kit 601 by being mounted on the holding unit 600A. Becomes

After a necessary operation such as turning on a power switch (not shown), key 452 is operated to switch SW4.
16 causes the external antenna 395 to be selected.
, And a wireless communication with the base station can be performed by the wireless communication line.

At this time, the power supply unit 460 is connected to the portable telephone 400.
The required power is obtained from the battery 190 loaded therein, but it is possible to obtain power from the BATT 325 via the holder 600 by operating the Key 452. BA
The power supply unit 460 having received the power supply from the TT 325 converts the power into a voltage corresponding to each circuit in the mobile phone 400 and supplies the voltage to each circuit. When the controller 501 recognizes the attachment of the connector 501, the control unit 450 may automatically switch the SW 480 to the BATT 325 side even without operating the Key 452.

The sound supplied to the microphone 370 in a hands-free manner after the line setting is output from the microphone 370 as an analog audio signal, and the signal line 645, the amplifier 642,
A / D (D / A) converter 64 via signal line 641
Input to 0. The signal converted into a digital signal by the A / D (D / A) converter 640 is input to the audio processing unit 630 via the signal line 632.

In the audio processing section 630, filtering, amplification and the like are performed. Data output from the audio processing unit 630 via the data bus 612 is transmitted to the control unit 610.
Is converted into a data string necessary for exchange with the mobile phone 400 and transmitted to the serial I / F unit 650.

This data string is converted into a serial digital signal by a serial I / F section 610,
59, the amplifier 658, and the signal line 657,
56. During this time, in the amplifier 658, the digital signal is subjected to power amplification sufficient to drive the light emitting unit 656.

The digital signal subjected to E / O conversion in light emitting section 656 is supplied as an optical signal to light receiving section 473 provided on bottom section 400A of portable telephone 400. Then, in the light receiving section 473, the digital signal is converted into an electric signal again.

The digital signal converted by the light receiving section 473 into an electric signal is divided into a signal line 473, an amplifier 474, and a signal line 4.
The data is supplied to a serial I / F unit 456 via the interface 75 and is converted into parallel data that can be processed by the control unit 450 in the serial I / F unit 456.

The serial I / F unit 456 to the control unit 450
Are subjected to necessary processing such as data shaping and error correction in the control unit 450. As a result, error bits and the like are removed from the digital signal, and only audio data faithful to the audio supplied to the microphone 370 is extracted.

From the control unit 450 to B. The audio data supplied to the B processing unit 440 is subjected to processing such as audio encoding and audio compression corresponding to the system of the mobile phone system, and transmitted to the wireless transmission unit 430.

For example, in the case of the CDMA system, speech processing such as spreading coding, despreading, and QCELP is performed.
B. This is performed by the B processing unit 440. Further, B. B processing unit 440
Cancels the echo caused by the acoustic coupling between the microphone 444 and the receiver 442.

Next, the voice data subjected to the necessary modulation by the radio transmitting unit 430 and loaded on the carrier is Dup 412,
Power is radiated from the external antenna 395 to the air via the SW 416, the terminal 417, the interface unit 603, and the power amplifying unit 690, and is received by the base station.

Thus, the voice of this side can be transmitted hands-free to the other party who is talking.

On the other hand, the voice data wirelessly transmitted from the base station follows the reverse route to the above, and the external antenna 39
5, transmitted to the wireless reception unit 420 via the power amplification unit 690, the interface unit 603, the terminal 417, the SW 416, and the Dup 412.

Radio receiving section 420 demodulates a high-frequency signal including audio data, and outputs the demodulated result to B.P. B processing unit 440
To supply.

The demodulated signal has a B processing unit 4
At 40, processing such as voice decoding and voice decompression is performed, and finally waveform shaping and error correction are performed at the control unit 450, and the data is extracted as voice data.

The audio data output from the control unit 450 is converted into serial data by the serial I / F unit 456 and sent to the light emitting unit 476 via the signal line 479, the amplifier 478, and the signal line 477.

The optical signal corresponding to the audio data E / O converted by the light emitting section 476 is received by the light receiving section 652 on the holder 600 side, and is again converted into an electric signal.

The audio data converted again into an electric signal by the light receiving section 652 includes a signal line 653, an amplifier 654, and a signal line 6.
The data is supplied to the serial I / F unit 650 via the interface 55, and is converted into parallel data that can be processed by the next control unit 610 in the serial I / F unit 650.

When the parallel data is supplied to the control section 610, it is converted into a data string necessary for driving the speaker 360, and is supplied to the audio processing section 630.

The audio processing unit 63 amplifies and filters the data sequence, and the D / A converter 640 performs D / A conversion. D / A converter 6
The analog signal output from 40 is supplied to speaker 360 via signal line 634, amplifier 644, and signal line 646.

As a result, the voice of the other party who is talking can be heard hands-free through the speaker 360.

(A-3) Effect of First Embodiment As described above, according to the first embodiment, the car kit 60
1 and the voice information of the mobile phone 400 are connected by an optical signal, so there is no need for voltage conversion even if there is a difference in the logic level between the two devices. Engine noise can be prevented, and is not related to electrostatic noise generated during use of a conventional connector.

Further, the coaxial cable 500 used in the present embodiment has a simple structure because there is no need to transmit a low frequency signal. Therefore, the structure of the connector 501 is also simple and small in size as compared with the conventional connector 201. Configurable at low cost.

In the present embodiment, since the exchange of signals between the portable telephone 400 and the holder 600 is performed serially, the number of signal lines and the number of terminals are smaller than those of the conventional one, and the sizes of the portable telephone 400 and the holder 600 are small. Can be made smaller and lighter.

(B) Second Embodiment Hereinafter, a case where the mobile communication terminal according to the present invention is applied to a mobile phone and an adapter device is applied to a car kit used by attaching to an automobile, similarly to the first embodiment. The second embodiment will be described as an example.

The second embodiment is characterized by the external shape of the portable telephone and the holder and the arrangement of the light-emitting unit and the light-receiving unit. The internal electronic circuit, the key and the like and the connection relation are shown in FIG. The components are the same as those in the first embodiment shown, and the corresponding components are denoted by the same reference numerals and detailed description thereof will be omitted.

(B-1) Configuration and Operation of the Second Embodiment FIG. 5 shows the configuration of a portable telephone 700 and a car kit holder 800 according to the second embodiment. Note that the holder 8
The illustration of the components of the car kit other than 00, that is, the external antenna, the speaker, and the like is omitted.

Referring to FIGS. 5A and 5B, front view 700 of portable telephone 700 on which Key 452 is arranged is shown.
The back surface 700B, which is the surface opposite to A,
In the illustrated state where the mobile phone 700 is mounted at 0, the mobile phone 700 is buried under the reference surface 800B of the holder 800 and is securely mounted.

In this mounted state, the portable telephone 70
0, and a substrate 401 on which a control unit 450 and the like are mounted.
Is at substantially the same height as the reference plane 800B (that is, the position in the direction of arrow H is the same).

The light emitting section 476 and the light receiving section 472
As shown in FIG. 5C, is disposed in close contact with the casing of the left side portion 700D of the mobile phone 400.
At portions corresponding to the light emitting unit 476 and the light receiving unit 472 of the casing, for example, transmission windows 701 and 702 that transmit infrared rays used for optical communication based on the IrDA (infrared data communication) standard are provided. Between adjacent transmission windows 701 and 702, a light shielding portion 703 that does not transmit infrared light is formed.

Therefore, the light emitting section 476 and the light receiving section 472 mounted on the substrate 401 are not mounted in this state.
As shown in (B), it is located on the reference plane 800B.

On the other hand, a holding portion 800A having an inverted “L” -shaped cross section projecting upward from the reference surface 800B of the holder 800, that is, in the direction of the arrow H, has a tip portion 800A.
C covers a part of the front face 700A of the mobile phone 700, and is formed in a shape to securely grip the front face.

As shown in FIG. 5B, the control unit 610
Signal line 65 extending upward from substrate 602 on which
The light receiving section 652 connected to the light emitting section 4
76 are arranged.

As shown in FIG. 5C, the light emitting section 656 and the light receiving section 652 are also provided with transmission windows 801 and 802 for transmitting infrared rays, and a light shielding section 803 therebetween. .

Therefore, at the time of mounting, the portable telephone 700 is securely held by the holder 800 of the car kit, and both the light emitting units 476 and 656 and the light receiving unit 47 are provided.
2 and 652 are almost in close contact with each other, and enable optical communication with low power consumption.

The tip portion 800C of the holding portion 800A not only contributes to the holding of the mobile phone 700, but also emits infrared light of the surrounding environment for optical communication between the light emitting portion 476 and the light receiving portion 652 and the light emitting portion 656 and the light receiving portion 472. It also has the function of preventing mixing.

The light emitting section 4 of the portable telephone 700
FIG. 6 shows an example of a change in the arrangement of the light-receiving unit 76 and the light-receiving unit 472.

In FIG. 6, the shaded area is the area where the light emitting section 476 and the light receiving section 472 can be arranged.
Also in this case, the light emitting unit 476 and the light receiving unit 472 are arranged close to each other. For example, the light emitting unit 472 is connected to the left side 700D.
If the light receiving section 472 is separately arranged on the right side section 700C, optical communication with a personal computer or the like becomes difficult.

(B-2) Effects of the Second Embodiment As described above, according to the second embodiment, in addition to the same effects as those of the first embodiment, the mobile phone 700 and the holder 8
Between 00 and 00, optical communication with low power consumption and low noise can be performed.

Further, since the light emitting section 476 and the light receiving section 472 of the portable telephone 700 are collected on the left side section 700D of the portable telephone 700, it is convenient to perform optical communication with AV equipment other than the car kit, a personal computer, and the like. .

(C) Other Embodiments In the above description, the holder of the car kit includes the power amplifier (690). However, a holder without the power amplifier may be used. In this case, even in the mounted state, the mobile phone communicates with the base station using its own antenna (411). In addition, the car kit includes a speaker, a microphone,
Any one or two of the batteries may be missing, and a different type of accessory device may be connected.

Further, the adapter device to which the portable telephone is mounted does not necessarily need to be a (car kit) device mounted on a moving body such as an automobile, but may be an adapter device used by being mounted on a building or the like. .

In addition to the mobile telephone, other types of mobile telephones such as a PHS telephone can be used, and a mobile communication terminal such as a digital camera or a portable information terminal other than the mobile telephone may be used.

That is, the present invention provides a mobile communication terminal provided with an interface for changing an operation environment by connecting to an adapter device, and connecting the mobile communication terminal to change the operation environment of the mobile communication terminal. The present invention can be widely applied to an adapter device having an interface for performing the operation.

[0086]

As described above, according to the present invention, even when the logic levels do not match between the mobile communication terminal and its adapter device, there is no need to perform voltage conversion at the interface between the two and the structure of the interface is reduced. Does not complicate. Further, there is no influence of the potential difference of the analog ground, and there is no influence of engine noise even when the adapter device is mounted on a vehicle.

Further, when a wired connection is made between the mobile communication terminal and the adapter device by, for example, a coaxial cable or the like,
The form of the coaxial cable and its connector portion is simpler than the conventional one, and it is easy to reduce the size and cost of the mobile communication terminal and the adapter device. Also, the possibility of electrostatic noise entering from the connector portion is low.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a mobile phone and a car kit according to a first embodiment.

FIG. 2 is a schematic view of a conventional mobile phone and a car kit.

FIG. 3 is an external view of a conventional mobile phone and a car kit.

FIG. 4 is an external view of a mobile phone and a car kit according to the first embodiment.

FIG. 5 is a schematic diagram of a mobile phone and a holder mounted state according to a second embodiment.

FIG. 6 is an explanatory diagram showing an arrangement of a light emitting unit and a light receiving unit of the mobile phone according to the second embodiment.

[Explanation of symbols]

100, 400: mobile phone, 190: battery, 300 ...
Control unit, 325: battery (BATT), 36
0: speaker, 370, 444: microphone, 395, 41
DESCRIPTION OF SYMBOLS 1 ... Antenna, 420 ... Wireless transmission part, 430 ... Wireless reception part, 442 ... Receiver, 460 ... Power supply part, 472, 65
2 ... light receiving section, 476, 656 ... light emitting section, 600 ... holder, 650 ... serial I / F section.

Claims (15)

[Claims] 1. A mobile communication terminal having an interface for changing an operation environment by connecting to an adapter device, wherein at least a part for information transmission in the interface performs optical communication with the adapter device. A mobile communication terminal, wherein the mobile communication terminal is an optical interface. 2. The mobile communication terminal according to claim 1, wherein the electric signal targeted by the first optical interface is:
A mobile communication terminal comprising at least a low-frequency electric signal. 3. The mobile communication terminal according to claim 1, wherein the mobile communication terminal having a built-in power source has at least a power source of the adapter device as a power source for driving the first optical interface. A switch for selecting a power source, and further comprising: an amplifier for driving the first optical interface; and means for changing an amplification degree of the amplifier according to a power source selected by the switch. Characteristic mobile communication terminal. 4. The mobile communication terminal according to claim 1, wherein the first optical interface transmits a light signal to the adapter device and receives the light signal from the adapter device. The light receiving unit is a mobile communication terminal, which is arranged to be concentrated on a local portion of an outer surface of the mobile communication terminal. 5. The mobile communication terminal according to claim 1, wherein said mobile communication terminal is a mobile telephone, and said optical communication is for supplying an audio signal to a modulation circuit built in said mobile telephone. Alternatively, the mobile communication terminal is a communication for supplying an audio signal output from a demodulation circuit built in the mobile telephone to the adapter device. 6. An adapter device having an interface for changing an operation environment of the mobile communication terminal by connecting the mobile communication terminal, wherein at least a part for information transmission in the interface is the mobile device. An adapter device, which is a second optical interface for performing optical communication with a communication terminal. 7. The adapter device according to claim 6, wherein the electrical signal targeted by the second optical interface is:
An adapter device comprising at least a low-frequency electric signal. 8. The adapter device according to claim 6, further comprising a power source separate from the mobile communication terminal. 9. The adapter device according to claim 6, wherein a light emitting unit for transmitting an optical signal to the mobile communication terminal and receiving the optical signal from the mobile communication terminal in the second optical interface. The adapter device is characterized in that the light receiving unit is arranged to be concentrated locally on the outer surface of the adapter device. 10. The adapter device according to claim 6, further comprising: means for optically blocking a path of optical communication with the mobile communication terminal from a surrounding environment. 11. The adapter device according to claim 6, further comprising: means for securely holding the mobile communication terminal. 12. The adapter device according to claim 6, wherein when the mobile communication terminal is a mobile telephone, a microphone of the mobile telephone is connected to a modulation circuit built in the mobile telephone. An adapter device comprising a microphone for supplying an audio signal with different input characteristics. 13. The adapter device according to claim 6, wherein when the mobile communication terminal is a mobile telephone, an audio signal transmitted from a demodulation circuit incorporated in the mobile telephone is transmitted to the mobile communication terminal. An adapter device comprising a speaker for outputting with an output characteristic different from that of a telephone receiver. 14. The adapter device according to claim 6, wherein when the mobile communication terminal is a mobile telephone, the mobile communication terminal is connected to a modulation circuit or a demodulation circuit built in the mobile telephone. An adapter device comprising an external antenna having characteristics different from those of the above antenna. 15. The adapter device according to claim 6, wherein when the mobile communication terminal is a mobile telephone, at least a battery connected to the mobile telephone is provided. .