JPH0256868B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a digital telephone that exchanges information with an exchange using digital signals.

In recent years, digital telephones have been developed that use a time-division multiplexing method using digital signals to send and receive information to and from an exchange. A selection signal for selecting the other party of a digital signal corresponding to Unless a call request signal is sent and it is accepted by the exchange, it is not possible to send a selection signal even if the pushbutton dial is operated, or even if a selection signal is sent, This has become ignored on the exchange side.

Therefore, conventional digital telephones have the disadvantage that they cannot provide center access services such as seat reservation services or terminal-to-terminal services that are performed by transmitting only selection signals during a call.

As a countermeasure for this, during a call, a signal such as a special number is sent to indicate that the signal is to be sent to the other party rather than to the exchange, and this is followed by a selection signal. The idea is to either convert the subsequent selection signal into a two-frequency signal and transfer it to the other party via the audio channel in the time-division multiplexed signal, or to transfer the selection signal as it is to the other party. It will be done.

However, in this case, the following drawbacks occur.

(1) When converting a selection signal into a two-frequency signal at an exchange, the exchange must have a function to determine the type of signal being sent, a function to convert it to a two-frequency signal, and a function to insert the two-frequency signal into the audio channel. However, the hardware and software configuration becomes complicated and economic efficiency deteriorates.

(2) If the selection signal is transferred directly to the other party at the exchange, a function to transfer the signal transparently, such as a common line signal path, is required within the telephone network, and if the other party is an analog system, The exchange that accommodates the other party must have a function to convert the selection signal into a two-frequency signal, and the exchange must be renovated, resulting in extremely poor economic efficiency.

(3) Also, the common drawbacks in cases (1) and (2) are:
When a subscriber requests seat service, etc., special operations are required, and the operability is significantly degraded compared to operations using current analog telephones.

The present invention has an object of fundamentally solving these drawbacks, and includes a signal control unit including a circuit that generates a selection signal of a digital signal for selecting the other party in response to a dial operation, and A circuit that generates a frequency signal in response to a dial operation, and a switch that switches the output signal of the circuit that generates a two-frequency signal under the control of a signal control unit when the dial is operated as a transmission signal and sends it to the exchange side. ,
To provide an extremely effective digital telephone that can simultaneously generate a selection signal and a two-frequency signal for each dial operation and send these signals to an exchange via a signal channel and a voice channel, respectively.

The details of the present invention will be explained below with reference to block diagrams showing embodiments.

In Fig. 1, 1 is a line terminal to which a subscriber line is connected, 2 is a switch, 3 is a transmission termination section, 4 is a line termination section, 5 is a CODEC, 6 is a signal control section, and 7 is a changeover switch. , 8 is a telephone call circuit, 9 is a calling amplifier, 10 is a sounder, 11 is a call request button during a call, 12 is a push button dial, 13 is a transmitter, 14 is a receiver, 15 is a two-frequency analog signal output. This is a signal generation circuit.

Here, when making a call, press the push button dial 12.
When pressed, the signal control section 6 generates a digital signal selection signal corresponding to the pressed dial number, and in order to provide this to the line termination section 4, this is inserted into the signal channel at the line termination section 4, It is transmitted to the exchange via the transmission termination section 3.

At the same time, a two-frequency signal corresponding to the pressed dial number is generated by the two-frequency signal generating circuit 15, and the changeover switch 7 is switched to the side opposite to that shown in FIG. 1 under control from the signal control section 6. , the output of the two-frequency signal generating circuit 15 is given to the codec 5 in place of the outgoing voice signal from the communication circuit 8, inserted into the voice channel at the line termination section 4, and then sent to the exchange via the transmission termination section 3. Sent.

On the other hand, at this time, the output of the two-frequency signal generating circuit 15 is applied to the communication circuit 8 via the changeover switch 7 instead of the receiving output of the codec 5, and is sent out from the receiver 14 as a dial confirmation tone.

Note that a similar operation is performed when the pushbutton dial 12 is pressed during a call.

However, if the pushbutton dial 12 is pressed without pressing the call request button 11, the selection signal is sent to the exchange, but since the call request signal was not sent in advance, the exchange does not send the selection signal. Ignore the selection signal that is sent to you.

Note that if you press the pushbutton dial 12 without pressing the call request button 11 during a call,
It is also possible to configure the signal control section 6 so as not to generate the selection signal.

FIG. 2 shows another embodiment, and 1 to 14 are the first
It is the same as that shown in the figure, and 16 is a two-frequency signal generation circuit whose output is a digital signal.

In FIG. 1, the output of the two-frequency signal generation circuit 15 is switched with the transmission signal from the communication circuit 8 and is applied to the codec 5, where it is digitized and transmitted to the other party. On the other hand,
In FIG. 2, a two-frequency signal generating circuit 16 generates a digitized two-frequency signal, which is switched with the digitized transmission signal from the codec 5 and then transmitted to the other party. ing.

In addition, the transmission termination unit 3 includes a switch 2
extracting power from the subscriber line in response to the turning on of the
It performs automatic equalization according to the characteristics of the subscriber line, establishes synchronization with the exchange side, and exchanges between 2-wire circuits and 4-wire circuits. assembly and disassembly,
It performs speed conversion between the signal transmission speed on the subscriber line side and the signal transmission speed on the codec 5 and signal control section 6 sides.

Further, the codec 5 encodes the transmitted voice signal from the transmitter 13 via the telephone call circuit 8 and supplies it to the line termination unit 4, and decodes the received coded signal from the same termination unit 4, The signal control unit 6 drives the amplifier 9 in response to a calling signal from the line termination unit 4, sends a selection signal to the line termination unit 4 in response to the operation of the pushbutton dial 12, etc. is being carried out.

In addition, depending on the operation of the pushbutton dial 12, 2
The two-frequency signal transmission from the frequency signal generation circuits 15 and 16 and the selection signal transmission from the signal control section 6 are performed at the same time, and the numbers indicated by these contents are decoded on the exchange side and numbered. After determining whether the other party's selection request is a request for a special service, the two-frequency signal transmitted through the voice channel is treated as valid when a special service is requested.

As is clear from the above description, according to the present invention, the following effects can be obtained.

(1) It becomes possible to provide center access services or terminal-to-terminal services, etc., which were not possible using conventional digital telephones.

(2) It is economical because center access services or terminal-to-terminal services can be provided with a simple configuration without adding any special functions to the exchange.

(3) When requesting a service, only dialing is required, so the operating procedure is the same as with conventional analog telephones.

(4) Since the selection signal and the two-frequency signal are generated simultaneously each time the dial is operated, the dial confirmation tone can be heard from the receiver.

Therefore, remarkable effects can be obtained as a digital telephone for various uses.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing another embodiment. 6... Signal control unit, 12... Push button dial, 15, 16... Dual frequency signal generation circuit.

Claims (1)

[Claims] 1. In a digital telephone that sends and receives information to and from an exchange using digital signals, a signal control section includes a circuit that generates a digital signal selection signal for selecting the other party in response to a dial operation, and a two-frequency wave corresponding to the selection signal. a circuit that generates a signal in response to the dial operation; and a circuit that is controlled by the signal control unit at the time of the dial operation and that switches the output signal of the circuit that generates the two-frequency signal to a transmission signal and sends it to the exchange side. Set up a switch,
A digital telephone set, characterized in that the selection signal and the two-frequency signal are simultaneously generated and sent to the exchange for each dial operation.