JPH0224309Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a central office line incoming call control circuit for a small simple exchange telephone device.

In general, a simple exchange telephone device, including a small simple exchange telephone device, is a device that can make and receive calls to and from a central office line as well as make inter-extension calls. When making a call to a central office line from an extension of a simple exchange telephone device, the extension telephone and the central office line are connected only after the caller lifts the handset of the extension telephone and indicates his/her intention to make a call to the central office line. It's becoming like that. This is to prevent the central office exchange from being unnecessarily captured when the handset is lifted for the purpose of making an internal call.

Therefore, in the simple exchange telephone device, the office line and the extension telephone are not directly connected at all times. For this reason, an incoming call signal monitoring circuit is installed on the office line to detect incoming call signals.

An example of a central office line incoming call control circuit in a conventional small simple exchange telephone device is as described below.

In the method of displaying a ringing signal by making the speaker of the extension telephone ring, the central office line is provided with an incoming ringing signal monitoring circuit, and an audible signal tone generating circuit is activated based on the signal detection information detected by this incoming ringing signal monitoring circuit. This output is sent to the extension phone's speaker circuit, causing the speaker to ring.

In addition, in the method of displaying a ringing signal by ringing the bell of an extension telephone, the extension telephone is generally not connected to the central office line, so the signal detection information detected by the incoming ringing signal monitoring circuit installed in the central office line is also used. Based on this, the bell ringing signal sound generation circuit is activated, and the output is sent to the ringing bell circuit of the extension telephone to ring the bell.

The above-mentioned system uses a dedicated signal tone generating circuit for each incoming call signal from the central office line, making it expensive and bulky. Even if these signal tone generating circuits were to be used in common for calling the other party in the case of internal communication, the problem would be that the capacity would be large and the cost would be high.

The present invention was devised to eliminate the above-mentioned drawbacks of the conventional technology, and uses the output of an incoming ringing signal monitoring circuit installed in the central office line to start a control device and operate a relay in a circuit corresponding to an extension telephone. According to
A central office line incoming call control circuit that connects the office line receiving an incoming call signal and the extension telephone at the contact point, and allows the extension telephone to directly ring and display an incoming call in response to the incoming call signal from the office. The purpose is to provide.

The present invention will be described in detail below with reference to the drawings.

The drawing shows a central office line incoming call control circuit according to an embodiment of the present invention. In the figure, 1 is a central office line, and 2 is an incoming call signal monitoring circuit. There is. 21 generally as shown in fig.
is a capacitor, 22 is a resistor, 23 is a varistor, 24
25 represents a resistor, 25 represents a photocoupler, and 26 and 27 each represent a resistor. Further, 28 is a power supply for the photocoupler 25, and 29 is an incoming call signal detection information line that displays the potential between resistors 26 and 27 when the photocoupler 25 is turned on, that is, when an incoming call signal arrives. .

3 is a circuit corresponding to an extension telephone, and only the parts necessary for explaining the present invention are shown. 31 is a control relay, and when its contacts 32 and 33 operate, the office line 1 and the extension telephone 4 are connected. Reference numeral 34 indicates a control line of a control relay, and 35 indicates a portion constituting, for example, an extension intercommunication circuit. Reference numeral 5 denotes a control device which receives information from the incoming call signal detection information line 29 and controls the control relay 31 through the control line 34 of the control relay.

Next, the operation of this central office line incoming call control circuit will be explained.

When the station line incoming call signal arrives from station line 1,
This signal current is connected to the capacitor 21 of the incoming call signal monitoring circuit 2 - resistor 22 --- | ｜ ｜ ｜ Light-emitting diode of La 25 -- passes through the circuit.

When current flows through the light emitting diode of the photocoupler 25, the phototransistor is turned on, and the potential of the resistors 26 and 27 is displayed on the incoming call signal detection information line 29. Based on this information, the control device 5 operates the control relay 31 via the control line 34 of the control relay 31, and the office line 1 is connected to the extension telephone 4 by the operation of the contacts 32 and 33 thereof.

Since the intermittent office line incoming call signal is received on the office line 1, the extension telephone 4 rings directly by the office line incoming call signal. When the extension telephone 4 picks up the receiver and answers, the office equipment of the office line 1 stops sending out the office line incoming call signal and becomes ready for communication.

Incidentally, once the control relay 31 is activated, its operation is maintained by the control device 5 until the central office line call is terminated.

As explained above, according to the present invention, the incoming call signal monitoring circuit 2 sends signal detection information to the control device 5, and the control device 5 controls the relay 31 of the extension telephone corresponding circuit 3 based on this information. These operations connect the office line 1 and the extension telephone 4, and cause the extension telephone 4 to directly ring with the incoming call signal from the office line. This has the advantage that there is no need to install a signal generator.

Furthermore, even if a ringing signal generator is required for calling the other party in inter-extension calls, it can be used only for internal calls and its capacity can be reduced, making it more economical and more compact. There are effects such as being able to.

[Brief explanation of the drawing]

The drawing shows a central office line incoming call control circuit of a small simple switching telephone device representing an embodiment of the present invention. 1 is an office line, 2 is an incoming call signal monitoring circuit, 25 is a photocoupler, 3 is an extension telephone correspondence circuit, 31 is a control relay, 4 is an extension telephone, and 5 is a control device.

Claims (1)

[Scope of utility model registration request] An incoming call signal monitoring circuit is provided on the office line, and a relay contact circuit for connecting the office line and the extension telephone is provided in the extension telephone corresponding circuit to which the extension telephone is connected, and furthermore, the incoming call signal monitoring circuit detects By providing a control device that controls the relay contact circuit based on signal detection information, the extension telephone and the office line, which are normally disconnected, are connected when an incoming call signal from the office line arrives. 1. A central office line incoming call control circuit for a small simple exchange telephone device connected by a control device, wherein an incoming call signal from the central office line directly rings an extension telephone.