JPS61276442A - Starting system for modulator-demodulator - Google Patents

Abstract

PURPOSE:To automate the switching operation by allowing a control section of a modulator-demodulator to identify a specific character sent sequentially from a terminal equipment, to decide the coincidence between parity bit setting and a prescribed number and to send a character representing the start of the modulator-demodulator. CONSTITUTION:Modulator-demodulators 2-4 identify the setting of a character A representign the communication speed sent from a terminal device 1 and a character B representing a parity bit. When the devices 2-4 receive no B character after the character A is received twice, it is judged that the operation from the terminal device 1 is in error. Then an address character representing the number of the device 2 is sent from the terminal device 1 and a control secion 8 receiving the character allows a transmission section 6 to send the character sequence including the number of the device 2 to inform the start of the device 2 to the terminal device 1 when the number is identical to the set number by a switch 7. Thus, the switching operation is automated an the number of modulator-demodulators connected to the terminal device is increased.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for activating a modem device.

[Conventional technology]

Conventionally, in a configuration in which multiple modems are connected to one terminal at multiple points, a method for starting one modem involves connecting one terminal and the plurality of modems via a switching device. There is a method in which one modulation/demodulation device is selected by connecting and manually switching the switching device.

[Problem that the invention seeks to solve]

The conventional system has the disadvantage that the switching device limits the number of modulation and demodulation devices that can be connected to one terminal.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide an activation method that automatically performs a switching operation between a terminal and a modulation/demodulation device without using a switching device.

[Means for solving problems]

The modem startup method of the present invention includes a plurality of modems,
In the modem activation method, the modem is connected to a multi-point terminal, transmits and receives data to and from one of the modems at a predetermined communication speed, and has a terminal that is asynchronous and non-procedural with other devices. Each of the devices includes a receiving section that receives asynchronous data transmitted from the terminal, a transmitting section that transmits the response to the terminal, a control section that controls the operations of the receiving section and the transmitting section, and other modulation/demodulation. and a switch unit that sets a different number in the control unit, and the control unit determines the communication speed by identifying a specific first character transmitted from the terminal and received by the reception unit. Then, the receiving section and the transmitting section are set to that speed, and the second character indicating the parity pit setting of the data transmitted from the terminal and received by the receiving section and set in the terminal is used. determines the parity bit setting, and then determines that a third character indicating the number transmitted from the terminal and received by the receiving section matches a predetermined number; The fourth character indicating that the modulation/demodulation device has been activated is transmitted, and the terminal is then controlled to transmit information between the modulation and demodulation device.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG. Terminal 1, which is asynchronous with other devices and has no procedures, is modem device 2.
．． 3. 4 is multi-connected.

Each modem includes a receiving section 5 that receives asynchronous data transmitted from the terminal 1, a transmitting section 6 that transmits a response from the modem to the terminal 1, and a control section 8 that controls these. and a switch section 7 for setting the number of the modulator/demodulator. Here, the modem 20
The number is 2. The modem 30 number is 3. It is assumed that the modem 40 number is set to 4. Further, the modulators 2 to 4 can communicate with the terminal 1 at any of three types of communication speeds, and switching of the communication speeds is performed by instructing the receiving section 5 and the transmitting section 6 from the control section 8.

In the above configuration, the operation when starting the modem device 2 from the terminal 1 will be described below.

When the power is turned on to the modem devices 2 to 4, the control section 8
' Instructs the receiving unit 5 to receive data at the lowest speed of speeds in class a. In order to notify the modem of the terminal's communication speed, one specific character (hereinafter referred to as an input character) is determined and transmitted from terminal l at that communication speed. If this communication speed is the lowest of the three types, the receiving section 5 receives the input character in its original form, thereby identifying the multiple communication speed. On the other hand, when the communication speed is an intermediate speed among the three types, the receiving section 5 receives the incoming character in a different format, but since the format is known in advance, the intermediate communication speed can be identified.

Similarly, when the communication speed is the highest of the three speeds, the receiving section 5 receives the incoming character in a different format;
Since its form is known in advance, its maximum communication speed of 1 cm can be determined. Both the receiving section 5 and the transmitting section 6 are instructed to achieve the communication speed identified by K in this way.

Next, in order to confirm whether the set speed is correct, terminal 1 transmits N characters again. When this character is notified to the control unit 8 through the receiving unit 5,
The control unit 8 identifies whether the character is a character or not, and if it is a character, the control unit 8 becomes the receiving unit for the next character from the terminal 1. If it is a character other than the input character, the control unit 8 determines that the communication speed instruction is incorrect, instructs the receiving unit 5 and the transmitting unit 6 to set the communication speed to the lowest speed, and returns to the initial state. Return to

Next, in order for the modem devices 2 to 4 to identify whether the parity pit setting of the data set in the terminal 1 is a mark, a space, an even number, or an odd number, the terminal 1 sends a parity identification character (hereinafter referred to as This character t-
8 characters). The control unit 8 can determine what the parity pit setting of the terminal 1 is based on the 1 character received twice and the 9B character received next.

As described above, the modem devices 2 to 4 identify the communication speed and parity pit settings of the terminal 1. If the modem devices 2 to 4 do not receive the B character after receiving the input character twice, it is determined that the operation from the terminal 1 is incorrect,
The receiver 5 and the transmitter 6 are instructed to set the communication speed to the lowest, and the process returns to the initial state. Next, the terminal 1 transmits a character indicating the modulation/demodulation device 20 number (hereinafter, this character will be referred to as an address character). The control unit 8 that received the address character checks whether it is the same as the number set by the switch 7, and if it is the same,
In order to notify the terminal l that the modem [20] has been activated, the transmitter 6 transmits a character sequence containing the number of the modem 20. Also, if the address character is different from the number set with switch 7, the terminal IK
It does not send anything to the target and maintains that state until it receives an incoming character.

By the above method, communication is possible between the terminal 1 and the modem 2), and using a character other than the input character, from the terminal 1 via the control unit 8 of the modem 20,
It is possible to operate the functions provided in the modem.

If it is desired to end the control over the modulation/demodulation device 2, this is done by transmitting a character from the terminal 1. The modem control unit 8 of the modulation and demodulation devices 2 to 40 that has received the character,
The receiving section 5 and the transmitting section 6 are instructed to operate at the lowest communication speed and return to the initial state.

In a similar manner, from terminal 1 to modem 3 or 4
Activation can be applied to .

Note that although the above description has given an example in which three modems are connected at multiple points, the present invention does not depend on the number of modems.

The control unit 8 in each modem also controls input characters, 8
It monitors whether the character and address characters are received in that order, and if even one different character is received, it instructs the receiver 5 and the transmitter 6 to operate at the lowest communication speed, Return to initial state. This monitoring by the control unit 8) prevents the modem from being activated due to an erroneous operation from the terminal 1.

〔Effect of the invention〕

As explained above, the present invention has the advantage that the number of modulation/demodulation devices connected to a terminal can be relatively freely increased.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. 1...terminal, 2-4...modulation/demodulation device,
5... Receiving section, 6... Transmitting section, 7...
... Switch section, 8... Control section.

Claims (1)

[Claims] A modulation and demodulation device comprising a plurality of modulation and demodulation devices and a terminal that is connected to the modulation and demodulation devices at multiple points, transmits and receives data to and from one of the modulation and demodulation devices at a predetermined communication speed, and is asynchronous and non-procedural with other devices. In the activation method, each of the modulation and demodulation devices includes a receiving unit that receives asynchronous data transmitted from the terminal, a transmitting unit that transmits a response thereto to the terminal, and a control that controls operations of the receiving unit and the transmitting unit. and a switch unit that sets a number different from that of other modulation/demodulators in the control unit, and the control unit identifies a specific first character transmitted from the terminal and received by the reception unit. Determine the communication speed, set the receiving section and the transmitting section to the determined speed, and then set a parity hit for data transmitted from the terminal and received by the receiving section and set in the terminal. determining the parity bit setting based on a second character indicating the number, and then determining that a third character indicating the number transmitted from the terminal and received by the receiving unit matches a predetermined number; A fourth character indicating that the modem has been activated is transmitted to the terminal via the transmitter, and then control is performed to cause information transmission between the terminal and the modem. modem startup method.