JP2002300234A - Mobile telephone, communication adapter and mobile telephone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a communication adapter to clearly discriminate whether or not to be a charging correspondence type PHS through a PIAFS (personal handyphone system Internet access forum standard) connector and to charge the charging correspondence type PHS from the communication adapter. SOLUTION: When the communication adapter is connected to the connector, the PHS generates load fluctuations of a prescribed cycle to notify the communication adapter of being a charging correspondence device. When the communication adapter receives this communication, the communication adapter increases transmission power. The transmission power is supplied into the PHS through a feeding pin of the connector to charge a battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to, for example, PHS (Pe
The present invention relates to a mobile phone such as a rsonal handy phone system, a communication adapter connected to the mobile phone by a cable, and a mobile phone system including both.

[0002]

2. Description of the Related Art As a mobile phone, a PHS has a large transmission capacity compared to other mobile phones, and is suitable for high-speed data communication. It is also used as a transceiver. When using as a mobile phone,
Although it is driven by a built-in battery, on the other hand, when it is used by connecting to a personal computer or the like, it is possible to receive power from the personal computer through a cable. However, this power supply voltage is not high enough to charge the internal battery, and is used only for driving the PHS. The built-in battery is charged by separately preparing a charger, mounting the PHS thereon, and connecting a charging electrode provided on the bottom of the PHS housing or the like to the electrode of the charger.

[0003] By the way, recently, diversification of use of PHS,
With the prolonged use time, there is a tendency that a shortage of time for setting in the charger occurs. In addition, there is a demand for further effective use of the PHS communication connector.
For this reason, it has been studied to take measures to charge the built-in battery through the cable when the cable is connected to the communication connector.

In order to enable charging through the communication connector, the power supply voltage from a device such as a personal computer connected to the other end of the cable must be increased, and the power supply pin of the communication connector must be connected inside the PHS to the internal battery. It is sufficient to wire the charging path up to this point, and it is considered that there is no problem in feasibility.

[0005]

However, in this case, since the PHS already on the market is not chargeable, it is necessary to clearly distinguish the PHS from the new PHS which is chargeable on the personal computer side. Otherwise, if a non-chargeable PHS is erroneously connected to a personal computer whose voltage has been increased to a chargeable voltage, there is a concern that the operating performance cannot be guaranteed.

SUMMARY OF THE INVENTION In view of the above, the present invention clearly distinguishes a mobile phone not compatible with charging from a mobile phone compatible with charging and enables charging of a built-in battery only when a mobile phone compatible with charging is connected. It is an object of the present invention to provide a communication adapter devised to perform the above, a new mobile phone compatible with charging, and a mobile phone system including a set of such a mobile phone and a communication adapter.

[0007]

In order to achieve the above object, the present invention provides a mobile communication system comprising a serial data input / output connector having a power supply pin and capable of transmitting and receiving data via an external communication adapter and the serial data input / output connector. A telephone, detecting means for detecting that a communication adapter is connected to the serial data input / output connector, and charging detection device via the serial data input / output connector when detecting that the communication adapter is connected. Means for notifying the communication adapter that there is a signal through the serial data input / output connector, and a power supply pin is inserted into the connection line between the power supply pin of the serial data input / output connector and the built-in battery, and the required voltage is supplied from the communication adapter to the power supply pin. Charge control means for starting charge control for the built-in battery when the It is.

Here, the notifying means may be a pseudo load circuit configured to vary the load on the external communication adapter in a predetermined pattern or periodically. Further, the charge control means monitors the progress of charging of the built-in battery, and when it is determined that the internal battery has reached full charge, instructs the pseudo load circuit to stop the operation of the switch element. can do.

Further, the notifying means may be communication means for transmitting data indicating that the mobile phone is a rechargeable mobile telephone via a serial data input / output connector through a communication pin of the serial data input / output connector. . Further, as the connector, a 12-pin or 16-pin data communication connector can be used.

Further, it is preferable that the on / off cycle of the pseudo load circuit is different from the intermittent reception cycle of the mobile phone. In order to achieve the above object, a communication adapter according to the present invention is a communication adapter connected to a serial data input / output connector of a mobile phone via a cable. Receiving means for receiving a notification as to whether or not the mobile phone is a compatible mobile phone; power generating means capable of generating both required charging power and small power merely for driving the mobile phone; In this case, there is provided switching means for switching the transmission power of the power generation means to the required power for charging, and the transmission power is supplied to the mobile telephone through a power supply pin provided in the serial data input / output connector.

[0011] Here, when the notification as to whether or not the mobile phone is a charge-compatible mobile phone transmitted from the mobile phone is made in a form in which the charging load is periodically increased and / or decreased, the receiving means includes a serial port. Monitors the current and / or voltage of the power supply line to the power supply pin of the data input / output connector to extract load fluctuations, and determines whether or not the mobile phone is a chargeable mobile phone based on the extracted load fluctuation cycle. And a switching unit that switches the transmission power according to the determination result of the determination unit.

Further, the present invention is a mobile telephone system in which a mobile telephone having a serial data input / output connector having a power supply pin and an external communication adapter are connected by a cable via the serial data input / output connector. A mobile phone, detecting means for detecting whether a communication adapter is connected to the serial data input / output connector, and, when detecting that the communication adapter is connected, serially notifies that the mobile phone is a charging-compatible device. Means for transmitting through the data input / output connector, and inserted into the connection line between the power supply pin of the serial data input / output connector and the built-in battery, and when a required charging voltage is supplied to the power supply pin from the communication adapter, Charging control means for starting charging control, and a communication adapter is connected to the mobile telephone connected via a cable. Receiving means for receiving a notification of whether or not the mobile phone is a charging-compatible mobile phone transmitted through a data input / output connector, required power for charging, and low power merely for driving the mobile phone. Power generating means and, in the case of a charging-compatible mobile telephone, switching means for switching the transmission power of the power generation means to the required charging power, and the transmission power is moved through a power supply pin provided in the serial data input / output connector. It is characterized by supplying to the telephone.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <Overall Configuration> FIG. 1 shows an embodiment of the present invention, in which 1 is a PH as an example of a mobile telephone.
S and 2 are personal computers. The PHS 1 includes a transmission / reception circuit, a speaker, a battery, and the like. Since the transmitting and receiving circuit is known and has no direct relation to the subject of the present invention, the description is omitted. One side of the PHS case 11 is a PIAFS (PHS Internet Ac
cess Forum Standard) connector 12 is provided. One end of the cable 3 is connected to the connector 12. The other end of the cable 3 is connected to the PC card 4. The PC card 4 is inserted into the card slot 21 of the personal computer 2.

The PC card 4 has a built-in charging circuit. When the PHS 1 is connected as shown in FIG.
When 1 is a charge-capable type, charging of the built-in battery is started. FIG. 2 shows a main configuration inside the PC card 4 and the charge-compatible PHS. <Configuration of PC Card> Although the PC card 4 includes a communication interface circuit, it has no direct relation to the subject of the present invention, and is not shown, and only the circuit connected to the power line is shown. That is, the AC / DC converter 41, the current / voltage control circuit 42, and the load fluctuation detection circuit 43 are connected to the power line. The power line is connected to a power supply pin of the PIAFS connector 12, and supplies power to the inside of the PHS through the power supply pin.

The load fluctuation detecting circuit 43 is a circuit for determining whether the PHS 1 connected through the cable 3 is of a charging-compatible type or a non-charging type. PH for rechargeable PHS
Since the impedance of the power supply circuit inside S is periodically changed, the load fluctuation detection circuit 43
The change in the impedance is detected. The detailed circuit of the load fluctuation detecting circuit 43 is shown in FIG. 3, and the period of the load fluctuation is also observed, and is distinguished from the period at the time of intermittent reception in which the same load fluctuation occurs.

The current / voltage control circuit 42 receives the detection result of the load fluctuation detection circuit 43, and when the PHS is connected, supplies the supply voltage and the current to 5 V, for example.
If the non-charging type PHS is connected to 450 mA, it is switched to 3.8 V 100 mA. <Structure of PHS> The PHS 1 shown in FIG. 2 is of a charge-compatible type. A charge control circuit 14, a pseudo load circuit 15, a microcomputer 16, and a battery 17 are connected to a power supply pin.

The charge control circuit 14 performs switching between charging and non-charging of the battery 17 and, during charging, switching from constant current control to constant voltage control as charging proceeds. FIG.
Indicates a charge control circuit 14, which is composed of an IC 141 and a transistor 142. The microcomputer 141 includes the microcomputer 1
6, a charge / no-switch signal is input, and the voltage and current of the charging path to the battery 17 via the transistor 142 are monitored. Is reached, the amount of conduction of the transistor 142 is controlled so that charging proceeds at a constant voltage. Curves V and I in FIG. 5 show the charging voltage and the charging current controlled in such a manner.

The dummy load circuit 15 is, for example, a load circuit that is connected to a power supply pin in parallel with the battery 17 and is a series circuit of a resistor and a contactless switch circuit. Thus, the load on the charging circuit is changed over time, for example, as shown in FIG. In FIG. 6, T1 and T2 indicate timings when the switches are turned on. In the present embodiment, the resistance is set to 15 ohms.

FIG. 7 shows a load fluctuation waveform when the non-contact switch of the pseudo load circuit 15 is turned on and off. The contactless switch is turned on for 5 ms between T0 and T1.
The time interval between T0 and T1 is 0.6S. This period is different from the intermittent reception period (1.2 seconds) of the PHS. The microcomputer 16 performs on / off control of the charge control circuit, constant current / constant voltage control, and load variation control of the dummy load circuit. The control operation is shown in the flowchart of FIG. 9 and will be described later in detail.

<Configuration of PC Card Load Fluctuation Detection Circuit>
As shown in FIG. 3, the load fluctuation detecting circuit 43 includes a load fluctuation detecting section 431, a minute amplitude cutoff section 432, a pulse detecting section 433, a specific period detecting section 434, an integrator 435, a minute current detecting section 436, and an integrator 437. Consists of The load fluctuation detection unit 431 is a circuit unit that detects a current flowing through the power supply line L1 or L2 and a voltage between the lines L1 and L2. The reason for detecting both voltage and current is that the charge control circuit switches between constant current control and constant voltage control during charging, so that load fluctuations can be detected during any period. It is. That is, during the constant current control period, the load fluctuation is detected by the voltage, and during the constant voltage control period, the load fluctuation is detected by the current.

The minute-amplitude truncation unit 432 is a circuit for removing minute-amplitude pulses and noise components such as load fluctuations during intermittent reception. For example, a known circuit having a hysteresis characteristic is used. Pulse detector 43
Reference numeral 3 denotes a circuit for detecting a pulse from a passed signal without being truncated by the minute amplitude truncation unit 432. For example, it is realized by a linear voltage generating circuit that increases the output voltage value with time, and an analog circuit that resets a voltage signal generated from this circuit every time a pulse is output through the minute amplitude cutoff unit 432. . In the triangular wave obtained from this analog circuit, the signal level immediately before the reset of the triangular wave has a magnitude proportional to the pulse period (the time interval between the immediately preceding pulse and the current pulse).

The specific period detecting section 434 is a pulse detecting section 4
The triangular wave signal output from 33 is peak-held, and the hold value is compared with upper and lower threshold levels.
If the value is between the two threshold levels, it is determined that the cycle of the detection pulse is the load fluctuation cycle intended for charging. The determination output of the specific cycle detecting section 434 is integrated by the integrator 435 for several cycles and input to the current / voltage control circuit 42. When it is determined that the cycle of the detection pulse is the load variation cycle intended for charging, the integrated output O1 reaches a predetermined value, otherwise, it becomes equal to or less than the predetermined value.

The current detector 436 is connected to the power lines L1, L
2 is detected. The detected current is integrated for a predetermined time by the integrator 437, and it is determined from the magnitude of the integrated value whether or not the battery has reached full charge. Integrator 43
7 is input to the current / voltage control circuit 42. <Description of Overall Operation> FIG. 8 is a flowchart showing the operation of the current / voltage control circuit 42, and FIG. 9 is a flowchart of the PHS microcomputer. Hereinafter, the battery charging operation will be described based on these flowcharts. The PC card normally outputs 3.8 V and 100 mA (S81).
Therefore, when the PHS is connected to the cable,
The above voltage and current are supplied, and the load fluctuation detection circuit 43
This voltage and current are maintained unless a load change in HS is detected (S82). The charging voltage of the battery is 4.1
４4.2 V is required, and the above voltage value (3.8 V) is insufficient as a charging voltage. Therefore, in that case, it is used to supply the power required for the transmission / reception operation of the PHS.

On the other hand, if it is determined in step S82 that the integrated output O1 from the load fluctuation detection circuit 43 is a predetermined value, the process proceeds to step S83, where the output voltage and current are changed to 5V and 450mA. Is done. Since this voltage exceeds the required charging voltage, charging of the battery is started in the PHS. When a predetermined time has elapsed since the switching to the charging required voltage in step S83 (S84), the integrated output O2 of the load fluctuation detection circuit is monitored to determine that the value of the current flowing through the power supply lines L1 and L2 indicates full charge. It is determined whether the value is small (S8).
5). As a guide, if it is less than 3 mA, it is determined that the battery is fully charged. In addition, the reason why the process waits for a predetermined time in step S84 is to avoid a determination at a transient stage immediately after the start of charging.

If the full charge has not yet been reached and the integrated output O1 of the load fluctuation detecting circuit 43 remains at a predetermined value (S86), the required charging voltage and current are continuously output. On the other hand, if the integrated output O2 becomes a small value indicating full charge (S85), or if the integrated output O1 falls below a predetermined value (S86), the output voltage and current are reduced (S8).
1). Thereby, the charging is completed.

As can be understood from the above charging operation, the value of the integral output O1 is determined in step S82, so that the charging-compatible PHS that periodically turns on and off the dummy load circuit and the charge control circuit is connected. Then, the process proceeds to the charging process. When an existing non-charging type PHS having no pseudo load circuit is connected, 3.8 V, 100 mA is connected.
The voltage and current are supplied, and it can be avoided that the charging required voltage is erroneously applied.

Next, the processing on the PHS side will be described with reference to FIG. The flowchart of FIG.
Shows the control of the microcomputer. When the microcomputer detects that the cable is connected to the PIAFS connector, it determines that the charger is connected (S91). The on / off operation is instructed to the dummy load circuit (S92). Based on this instruction, the internal contactless switch starts on / off operation,
The load fluctuates in the pattern shown in FIG. After the start of the load change, the PC card detects the load change, waits for a time necessary to output the charging required voltage (S93), and determines the power supply voltage (S94).

When the power supply voltage is 5 V, the charge control circuit 1
4 is instructed to start charging control (S95). Upon receiving this instruction, if the battery is discharging, the charge control circuit 14 first performs charging with a constant current, and when a certain amount of charge is reached, switches to constant voltage control and continues charging. Control. If the battery discharge amount is small, the charging operation is continued from the beginning until the battery is fully charged while performing constant voltage control.

When the charging current reaches 3 mA or less and the battery is fully charged (S96) as the charging proceeds, the pseudo load circuit 15 stops the load fluctuation operation (S97), and the charging control circuit stops the charging control (S97). S98). Thereafter, the battery voltage, the battery temperature, and the like are monitored to determine whether or not a charging abnormality has occurred (S99). When it is determined that an abnormality has occurred, the abnormality is displayed through the display of the PHS (S100). Even if no abnormality has occurred, it is determined whether recharging is necessary based on the monitoring result of the battery voltage or the like (S101). If recharging is required, the process returns to the first step and returns to the first step. It is determined whether or not the card is connected to the card by a cable. If the card is connected, the charging sequence of steps S92 to S96 is executed again.

On the other hand, if it is determined in step S101 that recharging is unnecessary, it is confirmed that no PC card is connected (S102), and the process is terminated. In addition,
In step S94, if the voltage supplied through the power supply pin is 3.8 V, it is considered that the PC card is a conventional one that does not support charging. The control circuit stops the load change (S103). Then, after the connection of the PC card is released (S104), the process ends.

<Modifications> The present invention is not limited to the above embodiment, but can be implemented in various forms without departing from the spirit of the present invention. Hereinafter, several examples are listed. As a method of notifying the PC card that the PHS is chargeable, the above-described embodiment employs a method of causing a load change through the power supply pin. In addition to this, another serial interface of the PIAFS connector is used. A method of notifying that the PHS is a charge-compatible PHS through serial communication through a data communication pin may be used. Also, even in the method of causing a load change through the power supply pin as in the embodiment, after the PHS side detects the load change and switches the voltage, the method is such that the load change is stopped immediately. It can also be implemented. Further, the load fluctuation is periodic in the embodiment, but is not limited thereto, and may be performed in a form that fluctuates in a predetermined pattern. One of the patterns is to change the cycle regularly so as to lengthen or shorten it with time, and the other is to change the magnitude of the load when the switch element is turned on regularly. It is. In order to change the magnitude of the load, a method of preparing a plurality of resistors connected in series with the switch element, selectively switching these, and connecting the switch element to the switch element can be considered. In the embodiment, both the voltage fluctuation and the current fluctuation are detected as a method of detecting the load fluctuation on the PC card side, but only one of them may be detected. In that case, it is necessary to increase the fluctuation of the load amount to facilitate the current detection on the PC card side. For this purpose, the battery 17 is synchronized with the on / off of the switch of the dummy load circuit 15.
It is desirable to control the charge control circuit 14 to interrupt the charge path to the battery. FIG. 10 shows a load fluctuation waveform when the on / off of the contactless switch of the pseudo load circuit 15 and the intermittent operation of the charging path of the charging control circuit 14 are performed in synchronization. At T0, both the transistor and the charging path are disconnected, and at T1, both are conductive. The switch is turned off between T1 and T2, the charging path is conducted, and the battery is being charged. In the embodiments, the PIAFS connector is used as the connector, but the present invention is not limited to this, and a 12-pin or 16-pin data communication connector can be used. The pseudo load circuit is connected to the power supply pin in parallel with the battery, but may be connected in series and implemented.

[0032]

As described above, the present invention is a mobile telephone having a serial data input / output connector having a power supply pin and capable of transmitting / receiving data via an external communication adapter and the serial data input / output connector. Detecting means for detecting that a communication adapter is connected to the serial data input / output connector; and detecting that the communication adapter is connected to the serial data input / output connector. When the required voltage is inserted into the connection line between the power supply pin of the serial data input / output connector and the built-in battery and the required voltage is supplied from the communication adapter to the power supply pin, the charging control for the built-in battery is started. Therefore, the following effects can be obtained.

That is, if the communication adapter is connected, it is notified that the mobile phone is a rechargeable mobile phone. The communication adapter determines whether the connected mobile phone is a rechargeable device by receiving this notification. It is possible to clearly determine whether the device is not a sending device. Thus, it is possible to select whether the power for power supply is a large power required for charging or a power saving for merely driving the mobile phone.

Here, if the notifying means is a pseudo load circuit having a configuration in which a switch element that is periodically turned on and off is connected in parallel with a built-in battery to a power supply pin, the communication adapter monitors the power supply line. As a result, it is possible to receive a notification as to whether or not charging is supported from the mobile phone, and the line can be shared. Further, the charge control means monitors the progress of charging of the built-in battery, and when it is determined that the internal battery has reached full charge, instructs the pseudo load circuit to stop the operation of the switch element. If this is the case, the communication adapter can know the end of charging only by monitoring the load fluctuation, and can take measures such as prompt reduction of the transmission power.

Further, if the on / off cycle of the pseudo load circuit is made different from the intermittent reception cycle of the mobile phone, it is possible to prevent erroneous supply of the required power for charging to the mobile phone not supporting charging. I can do it. Also, the present invention
A communication adapter connected to the serial data input / output connector of the mobile phone via a cable, and receiving means for receiving a notification as to whether or not the mobile phone is a chargeable mobile phone through the serial data input / output connector from the connected mobile phone; A power generating means capable of generating both the required charging power and a small power merely for driving the mobile phone; and, in the case of a charging-capable mobile phone, switching the transmission power of the power generating means to the required charging power. Switching means for supplying transmission power to the mobile telephone through a power supply pin provided in the serial data input / output connector.
If a distinction is made as to whether S is a charge-compatible PHS or a non-charge-compatible PHS, power can be supplied to any of them.

[Brief description of the drawings]

FIG. 1 shows an example of a mobile telephone system according to the present invention.

FIG. 2 is a diagram showing a main part of an internal configuration of a PHS and a PC card.

FIG. 3 is a block diagram showing details of a load fluctuation detection circuit in the PC card.

FIG. 4 is a circuit diagram showing a charge control circuit in the PHS.

FIG. 5 is a charge characteristic diagram showing a state of charge control of a built-in battery.

FIG. 6 is a waveform diagram illustrating the on / off operation of the pseudo load circuit.

FIG. 7 is a waveform diagram showing a load change situation.

FIG. 8 is a flowchart showing a charge control operation of the PC card.

FIG. 9 is a flowchart showing an operation at the time of charging the PHS.

FIG. 10 is a waveform chart showing an example of load fluctuation.

[Explanation of symbols]

 1: PHS 2: personal computer 3: cable 4: PC card 11: case 12: connector 14: charge control circuit 15: pseudo load circuit 16: microcomputer 17: battery 41: AC / DC converter 42: current / voltage control circuit 43: Load fluctuation detection circuit 141: IC 142: Transistor 431: Load fluctuation detection circuit 432: Minute amplitude truncation unit 433: Pulse detection unit 434: Specific cycle detection unit 435: Integrator 436: Microcurrent detection unit 437: Integrator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H04M 1/725 H04B 7/26 YMF Term (Reference) 5B011 DA06 DA13 DB19 EA10 GG11 GG14 5G003 AA01 BA01 CA03 CA04 CA14 FA03 GC05 5K023 AA07 BB11 LL03 MM00 NN06 5K027 AA11 BB02 EE11 GG02 HH26 KK07 5K067 AA34 BB04 EE02 KK06

Claims (9)

[Claims] 1. A mobile telephone having a serial data input / output connector having a power supply pin and capable of transmitting and receiving data via an external communication adapter and the serial data input / output connector. Detecting means for detecting that the communication adapter is connected; and, when detecting that the communication adapter is connected, the serial data input / output connector to the communication adapter that the device is a charging-compatible device via the serial data input / output connector. Means to be notified through a power supply pin of the serial data input / output connector and the built-in battery. The charge control for the built-in battery is started when a required charging voltage is supplied from the communication adapter to the power supply pin. A mobile phone comprising: charging control means; 2. The mobile telephone according to claim 1, wherein said notifying means is a pseudo load circuit configured to vary a load on an external communication adapter in a predetermined pattern or periodically. 3. The charge control means monitors the progress of charging of the built-in battery and, when judging that the full charge has been reached, instructs the pseudo load circuit to stop the operation of the switch element. The mobile telephone according to claim 2, wherein 4. The communication device according to claim 1, wherein the notification unit is a communication unit that transmits data indicating that the mobile phone is a rechargeable mobile phone via a serial data input / output connector through a communication pin of the serial data input / output connector. Claim 1
Mobile phone described in. 5. The mobile telephone according to claim 1, wherein said connector is a 12-pin or 16-pin data communication connector. 6. The mobile telephone according to claim 2, wherein the on / off period of the dummy load circuit is different from the intermittent reception period of the mobile telephone. 7. A communication adapter connected to a serial data input / output connector of a mobile phone via a cable, wherein a notification as to whether or not the mobile phone is a chargeable mobile phone is transmitted from the connected mobile phone via a serial data input / output connector. Receiving means for receiving, power generating means capable of generating both required power for charging and small power for simply driving the mobile phone; and transmitting power of the power generating means for a charging-compatible mobile phone. Switching means for switching to required charging power, wherein the transmitting power is supplied to the mobile telephone through a power supply pin provided in the serial data input / output connector. 8. A notification as to whether or not the mobile phone is a charging-compatible mobile phone transmitted from a mobile phone is provided in a form in which a charging load is increased and / or decreased periodically or in a predetermined pattern. It is a charge-compatible mobile phone based on the load fluctuation extraction means that monitors the current and / or voltage of the power supply line to the power supply pin of the data input / output connector to extract load fluctuation, and the extracted load fluctuation pattern or cycle. 8. The communication adapter according to claim 7, further comprising: a determination unit configured to determine whether the transmission power is switched based on a determination result of the determination unit. 9. A mobile telephone having a serial data input / output connector having a power supply pin, and an external communication adapter,
A mobile telephone system connected by a cable via the serial data input / output connector, wherein the mobile phone is connected to a detection unit that detects whether a communication adapter is connected to the serial data input / output connector, and a communication adapter is connected to the mobile phone. If it is detected that the device is a charging-capable device, it is inserted into the connection line between the power supply pin of the serial data input / output connector and the built-in battery, and Charging control means for starting charging control of the built-in battery when a required charging voltage is supplied to the power supply pin from the communication adapter, and the communication adapter is transmitted from the cable-connected mobile telephone through the serial data input / output connector. A receiving means for receiving a notification as to whether or not the mobile phone is a rechargeable mobile phone; Power generating means capable of generating both electric power and small electric power merely for driving the mobile phone; and switching means for switching the transmission power of the power generating means to the required power for charging if the mobile phone is a chargeable mobile phone. A mobile telephone system comprising: transmitting power supplied to a mobile telephone through a power supply pin provided in the serial data input / output connector.