JP2001016348A - Automatic power control function of data modem - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically attain a power saving mode by operating a data modem connected to a host computer by an AT command given from the host computer, automatically canceling the power saving mode in a communication mode and supplying the power to secure a communication enable state and cutting the supply of power when a circuit cutoff command is received. SOLUTION: A power supply control circuit 4 is included in an AT command analysis part of a data modem to a data modem part. When the data modem part receives and ATD command serving as an originating command, the AT command analysis part supplies power to the data modem part. When the data modem receives an ATH command serving as a circuit cut command, the AT command analysis part cuts the supply of power to the data modem part. In regard to a data modem which transmits the data via a portable telephone set 9, the power supply of the telephone set 9 is cut as long as the telephone set 9 is set in a data transmission mode as well as when it is kept in a standby mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for automatically setting and canceling a power saving mode of a data modulation / demodulation device from a host computer.

[0002]

2. Description of the Related Art It has long been common for a host computer and a data modulator / demodulator to be connected by a system called EIA-RS-232C. EIA-RS-232
In C, signals called DTR and DSR are defined.

[0003] The DTR signal indicates that the host computer requests use of the data modem. The DSR signal is a response to the DTR signal and indicates that the data modem can be used.

Therefore, the DTR signal has been used to instruct the power on / off of the data modem from the host computer, and the DSR signal has been used to indicate the power-on state of the data modem.

Recently, a new system has been used for connection between a host computer and a data modem. A typical method is a PC card connection method.

In the case of a data modulator / demodulator connected to a host computer by a PC card, a signal for controlling the supply of power from the host computer to the inside of the PC card is defined. By controlling this signal, the power supply to the data modem is controlled.

[0007]

SUMMARY OF THE INVENTION EIA-RS-232
Since the C method requires a large connector, a thick cable, and both plus and minus power supplies, it is inconvenient to arrange the cable. In recent years, the size of the device has been reduced, and the device is no longer used.

On the other hand, in the PC card connection system,
As a terminal for controlling the supply of power to the inside of the card, Vp
p1 and Vpp2 have been defined. However, actually, the signals applied to these terminals are not merely positive / negative logic signals, but the power supply itself supplied to the data modem inside the PC card. Since large power control is required compared to a simple signal, a large-scale circuit using a dedicated controller or the like is required.

In order to control the supply of power to the inside of the PC card from the host computer, Pw
An rDwn register is provided. However, Pw
Since the rDwn register is a register unique to a PC card, if the PwrDwn register is used for power supply control, it is compatible with software for controlling a data modem having another host computer connection method, such as EIA-RS-232C. Disappears. The control software is dedicated to the PC card.

[0010]

The data modulator / demodulator for transmitting and receiving data via a public line is almost always controlled by AT commands, regardless of the type. In order to maintain compatibility with previously developed software, it is expected that AT commands will continue to be used in data modems.

Due to recent advances in semiconductor technology, only digital circuits can be driven with very little power. Since a circuit for analyzing an AT command from the host computer can be constituted only by a digital circuit, it can be driven with a small power. Even if a circuit for analyzing the AT command is utilized in the data modulation / demodulation device, the power consumption is hardly affected.

Further, even when further low power consumption is required, the sleep mode of the digital circuit can be easily realized. For example, when the character "A" of the AT command is received, a circuit that releases the sleep mode and activates the entire AT command analysis unit may be provided in the data modem.

On the other hand, the data modulation / demodulation unit is an analog circuit, and usually requires large power. In particular, in a device for wirelessly transmitting data, a large amount of power is required only by making the device stand by.

In the AT command, commands for transmission and line disconnection are defined. When performing data communication, a transmission command is always sent to the data modem before data communication, and a line disconnect command is always sent to the data modem when data communication is completed.

When the AT command analysis unit is configured to supply power to the data modulation / demodulation unit when receiving the transmission command, and to cut off the power supply to the data modulation / demodulation unit when receiving the line disconnection command, the host computer side performs data transmission. There is no need to supply power to the modem.

By realizing the power saving mode of the data modulation / demodulation device without rewriting the conventional software, by analyzing the AT command and controlling the power supply to the data modulation / demodulation device based on the received command. Can be.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a data modem, an AT
A power supply control circuit for the data modulation / demodulation unit is provided in the command analysis unit. When the data modem receives the ATD command, which is a transmission command, the AT command analyzer supplies power to the data modem. When the data modem receives the ATH command which is the line disconnection command,
The T command analysis unit cuts off power supply to the data modulation / demodulation unit.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the case of a data modulator / demodulator for transmitting data to a wireless public line via a mobile phone, when the mobile phone is set to a data transmission mode, the power of the mobile phone is shut off during standby. . A from host computer
When the T command is sent, the AT command analyzer turns on the power of the mobile phone. When data communication is completed and an ATH command is sent from the host computer, the power supply to the mobile phone is cut off.

[0019]

Conventionally, it has been necessary to provide a dedicated signal for power control of the data modem, or to provide a power control circuit on the host computer side. This has led to an increase in the size of the device main body and the complexity of the circuit on the host computer side.

According to the present invention, it is possible to easily reduce the size and power consumption of a data communication device without impairing software compatibility with a conventional device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a data modulation / demodulation device via a mobile phone according to an embodiment of the present invention. The PC card controls the power of the mobile phone based on an AT command sent from the host computer.

[Explanation of symbols]

 Reference Signs List 1 input sensor 1 2 input sensor 2 3 host computer 4 power supply control circuit 5 lithium ion rechargeable battery 6 solar cell 7 PC card interface 8 PC card 9 mobile phone

Claims (7)

[Claims] In a data modem connected to a host computer, a power saving mode is automatically released based on an AT command from the host computer to enable communication. A data modulation / demodulation device, which automatically enters a power saving mode based on a command. 2. The data modulation / demodulation device according to claim 1, wherein the AT command from the host computer which automatically releases the power saving mode and becomes communicable is an ATD command. 3. The data modulation / demodulation apparatus according to claim 1, wherein the AT command from the host computer which automatically releases the power saving mode and becomes communicable is a command other than the ATH command. 4. The data modulation / demodulation apparatus according to claim 1, wherein the AT command from the host computer which automatically enters the power saving mode is an ATH command. 5. The data modulation / demodulation device according to claim 1, wherein when a command or data is not received from a host computer for a predetermined period, a power saving mode is automatically set. 6. The data modulation / demodulation device according to claim 1, wherein the data modulation / demodulation device is connected to a host computer by a PC card, USB, or IEEE1394. 7. The data modulation / demodulation device according to claim 1, wherein the data modulation / demodulation device includes a wireless interface having a data communication function.