JPH03145852A - Digital electronic exchange - Google Patents

Abstract

PURPOSE:To recognize a busy state immediately while an opposite party is busy by providing a means detecting a MODEM trunk busy tone. CONSTITUTION:A control circuit of a MODEM trunk 1 monitors the state of an analog circuit from a MODEM 10. Moreover, as to the state of a digital circuit from the MODEM 10, the monitor of carrier detection and the control of terminal ready similarly to the case with a data terminal equipment are implemented. A busy tone detection circuit 11 is provided to a reception circuit at the analog signal side of the MODEM trunk 1 and since a connection opposite party is in communication with the other data terminal equipment, when a busy tone is returned, it is immediately detected.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to digital electronic exchanges.

[Conventional technology]

Conventionally, in a digital electronic exchange equipped with a modem pool trunk, a central control circuit (C
PU) 7 is connected to the central office line trunk 8. by a predetermined program. Modem trunk 1° digital line circuit 6. The program executed by the CPU 7, which controls the switch circuit 2, etc., does not need to be installed in each modem trunk 1 for each data adapter, but can be pooled for the entire exchange.
It has the ability to connect only when necessary. The modem 1° and the modem trunk 1 exchange analog data on the public network 9 with digital data on the data adapter 4 attached to the digital telephone 5, and now from the data terminal 3 to the data terminal on the public network 9. connection and data communication. When a dial command is entered from the keyboard of the data terminal 3, the data adapter 4 interprets it and dials through the digital telephone 5.The CPU 7 inputs a dial command from the data terminal 3 to dial the digital telephone 5. Select and reserve one of the modem trunks 1. When dialing to the public network 9 is completed, connect the reserved modem trunk 1 and wait for a carrier signal from the other party. By detecting the carrier, The data adapter 4 is notified of the completion of the connection and becomes ready for communication.

Now, let us consider a case where the partner terminal is communicating with another terminal. Needless to say, if the other party's terminal is busy, only a busy tone will be returned, and the modem 10 will not be able to detect the carrier. In consideration of such cases, normally the time required for communication to become established after dialing is completed is monitored, and if communication is not established even after a certain period of time, the other party's terminal is assumed to be busy and the line is restored. There is.

[Problem to be solved by the invention]

In such exchanges, not only do shared modems and modem trunks become unnecessarily occupied for a long time even when the other party is busy, but also it is necessary to install a large number of shared modems in order to avoid situations where there is no modem. and costs will inevitably increase.

[Means for solving problems]

The present invention includes a data adapter having an interface with a data terminal, a digital telephone that accommodates the data adapter, a digital line circuit that connects the digital telephone, and a modem trunk and a central office line trunk that are accommodated in a switch circuit. In a digital electronic exchange,
This configuration includes means for detecting a busy tone in the modem trunk.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Referring to FIGS. 1 and 2, which illustrate one embodiment of the present invention, the control circuit of modem trunk 1 monitors the status of analog circuits from modem 10, such as loop formation. Also, regarding the status of the digital circuit from the modem 10, a busy tone detection circuit 11 is installed in the receiving circuit on the analog signal side of the modem trunk 1, which monitors carrier detection and controls terminal readiness in the same way as the data terminal. It is configured so that it can be detected immediately if a busy tone is returned because the connected party is communicating with another data terminal. The modem trunk 1 is connected between a central office line trunk 8 for analog signal transmission and a digital line circuit 6 for digital signal transmission, and modulates and demodulates analog and digital signals.

Dials from the data terminal 3 are connected to the data adapter 4, digital telephone 5. Via the digital line circuit 6, the CPU
Sent to 7. The CPU 7 receives a dial from the data terminal 3, and in the case of connection to the public network 9, reserves the modem trunk 1 and dials the number received via the central office line trunk 8. After dialing is completed, the modem trunk 1 is connected, a carrier signal from the other party is waited for, and a carrier signal detection report is sent from the modem trunk 1 to the CPU 7. C
The PU7 activates the digital line circuit 6 based on the carrier signal detection report. The completion of the connection is notified to the data adapter 4 and data terminal 3 through the digital telephone 5. This results in
Transition to data communication enabled state.

On the other hand, if the connected party is communicating with another terminal, a busy tone is returned from the public network 9 after dialing is completed.If a busy tone is returned from the public network 9, it is detected by the modem trunk 1 and the CPU
Busy detection is reported to 7. The CPU 7 notifies the data adapter 4 and data terminal 3 through the digital line circuit 6 and the digital telephone 5 that the other party is talking. The data terminal 3 knows that the other party is talking and restores the line. As a result, the modem trunk 1 becomes empty and available for use by the next user.

〔Effect of the invention〕

As described above, according to the present invention, by providing means for detecting the modem trunk busy tone, it is possible to immediately recognize the busy state when the other party is talking. For this reason, lines and modem trunks are not put on hold unnecessarily, and because there are no modem trunks put on hold uselessly, it is possible to handle the system with a smaller number of modem trunks overall. As a result,
It is possible to reduce communication costs and communication equipment.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the detailed configuration of a modem trunk in one embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of a digital electronic exchange. 1... Modem trunk, 1... Busy sound detection circuit.

Claims (1)

[Claims] a data adapter having an interface with a data terminal; a digital telephone accommodating the data adapter;
a digital line circuit connecting the digital telephone;
A digital electronic exchange comprising a modem trunk and a central office line trunk accommodated in a switch circuit, characterized in that the modem trunk is provided with means for detecting a busy tone.