JPH0148717B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called central line oral transfer method for verbally transferring a central line call in a button telephone device to another telephone, and provides a confidential communication control function to a relay for selecting a communication path. Therefore, the circuit is simplified by not providing a separate dedicated relay for secret calls in each telephone set, but by providing one relay for maintaining the central line loop per central office line, which is shared by the main unit. Note that the central line verbal transfer method here refers to a method of verbally informing the transfer destination of the transfer, and refers to a central line transfer method that does not have a central line holding function in terms of circuitry.

In the conventional button telephone device of this type, as shown in Fig. 1, a relay P for secret communication on the central office line (only the contacts are shown in Fig. 1) is connected to each telephone TEL (when there is no need to distinguish, the (Do not add A or B at the beginning.). A telephone that is currently talking to the central office line C/O, such as a telephone that is transferred from A.TEL, for example, B.
The operation when verbally transferring the busy office line C/O to TEL is as follows.

Even if telephone B/TEL tries to interrupt the central office line C/O where telephone A/TEL is talking, the telephone B/TEL will be disconnected from the communication network by the operation of relay P.
NET is disconnected from the telephone lines L1 and L2, making it confidential and making it impossible to make intentional interruption calls.However, in this case, in terms of direct current, the telephone lines L1 and L
2 is connected to the resistor R, forming a DC loop to the central office line C/O.
If TEL verbally informs telephone B/TEL that it will be forwarded and then turns on, the DC loop caused by this resistor R does not end the call to the central office line C/O, and the telephone B/TEL The confidential communication relay P inside is restored, and its contact (continuous contact) switches from the resistor R to the communication network NET without momentary interruption of the DC loop, and the telephone B/TEL
is connected to the central office line C/O, allowing central office line transfer.

By the way, as shown in FIG. 2, in addition to the central office line communication lines L1 and L2, there are extension line communication lines P1 and P2.
If the above-mentioned conventional central office line oral transfer method is adopted in a button telephone device equipped with a telephone line, a relay RS for selecting a communication route (only the contacts are shown in Figure 2) is installed in each telephone TEL. Required in addition to the confidential communication relay P mentioned above, and if there are two relays, the telephone
The current consumed within the TEL increases, and when considering the line loss along the way, the power loss becomes considerably large.
In addition, in Figures 1 and 2, C1 and C2 are control lines, HS
is the switch contact point.

The present invention has been made in order to solve the above-mentioned conventional drawbacks, and an object of the present invention is to obtain a button telephone device that consumes less current within the telephone and requires fewer components.

For this purpose, in the present invention, it is necessary for each telephone set, which is controlled so that an interrupt call by a third party is prohibited to the central office line during a call, to have a resistor for maintaining the central office line loop. In this way, we do not need a secret relay for each phone, so we can minimize the increase in current consumption, and we believe that the phone can be configured with fewer parts. is equipped with only a relay for selecting a communication route, and a resistor and relay for holding the central line loop during transfer are provided in the main device in common for each telephone, and the relay for maintaining the central line loop is operated by a control signal from each telephone.・In addition to controlling the recovery, the relay for selecting the communication route will not operate even if a telephone that is not in a call on the central office line is captured, so that the relay has a privacy control function. did.

Embodiments of the present invention will be described below with reference to FIGS. 3 and 4.

FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is an explanatory diagram of the operation.

In Fig. 3, L1 and L2 are office line communication paths, P
1 and P2 are extension communication lines, C1 and C2 are control signal lines, C/O is the office line, ME is the main device, and TEL is the telephone (when referring to the two shown individually, it is the beginning)
A" or "B" is attached.) In the main device ME, R is a resistance as a means for holding the station line loop,
J is a relay as a connection means for connecting the above-mentioned resistor R to the station line loop, j is a contact of relay J,
COM (M) is a microcomputer, and in the telephone TEL, RS is a relay that serves as both a communication path selection means and a privacy control means, rs is a relay RS contact, HS is a switch contact, and LK is a central office line switch. NET is the communication network, and COM (T) is the microcomputer. In addition, it is assumed that the secret call function is provided only to central office line calls.

Relay RS in standby state (not in talking state)
The contact RS is located on the extension line P1 and P2 side, and when the switch is turned off (that is, when the handset is raised), the contact HS is closed and the telephone is disconnected.
TEL communication network NET is extension communication path P1, P2
is connected and you can make internal calls. In addition, when making a call on the central office line, pressing the central line switch on the telephone TEL closes the contact LK, and when this is read by the microcomputer COM (T), the relay RS operates and the contact RS switches, and the call is terminated. circuit network
NET is reconnected to the central office line communication paths L1 and L2, so when the switch is turned off, its contact HS closes, and the telephone TEL captures the central office line C/O, making it possible to talk to the central office line C/O. Become.

Telephone A/TEL is currently making a call to a central office line.
Assume that the central office line call is transferred to telephone B/TEL. In the state before transfer, relay RS is operating on telephone A/TEL, and relay RS is not operating on telephone B/TEL.

At time t1, telephone A/TEL, which is in communication with the central office line C/O, calls the central office line C/O to telephone B/TEL.
In order to transfer the call to , tell that to telephone B/TEL. When telephone B/TEL hooks off to interrupt the central office line C/O and presses the central office line button, the contact
HS is closed, and a central office line call request signal is input to the microcomputer COM (T) by contact LK, but at this time, relay RS in telephone B/TEL is activated because telephone A/TEL has not terminated the call yet. No, the phone B/TEL is on extension line P1,
It is connected to P2 and is confidential to the central office line C/O. In other words, in the case of a simple central office line interruption, the TEL of the telephone that made the interruption will be confidential, and
Since the relay RS does not operate, it has a secret control function.

The interrupt operation to the central office line C/O during a call from the above-mentioned telephone B/TEL is detected by the microcomputer COM (M) of the main device ME via the control signal lines C1 and C2, and the microcomputer COM (M) of the main device ME is thereby detected. M) operates relay J. Relay J
The contact j is closed by the operation of
A resistor R is connected between 2 and the telephone A/TEL which is in use, and the office line loop is maintained by both the telephone A/TEL and the resistor R from time t1 until time t2, which will be described later.

In this state, at time t2, telephone A.
When the TEL ends (that is, when the handset is put down), the switch contact HS opens, the connection between the telephone A/TEL and the office line C/O is released, and the relay RS is connected to the microcomputer COM (T ) and the contact rs switches to the extension communication paths P1 and P2. On the other hand, phone B.
On TEL, the end of call information of the above telephone A/TEL,
The microcomputer COM(T) receives it. At this time, the microcomputer COM (T) of the telephone B/TEL remembers that the office line switch was pressed earlier and its contact LK was closed.
This and the call termination information of the above telephone A/TEL (by opening the switch contact HS or relay
Obtained due to the restoration of RS, etc. ), the microcomputer COM(T) of the telephone B/TEL operates its relay RS and switches its contact rs to the central office line communication path L1, L2 side. As a result, telephone B/TEL becomes deprived and becomes able to talk to the central office line C/O (time t
3). Now, calls to the central office line C/O can be made using telephone A.
This means that the call was transferred from TEL to telephone B/TEL.

While the central office line call is transferred from telephone A/TEL to telephone B/TEL, that is, at time t in FIG.
2 to time t3 is maintained by a resistor R in the main device ME. In other words, even when changing connections between telephones A/TEL and B/TEL, there is no momentary interruption of the DC loop to the central office line C/O. This connection change time (time t2
- t3) is the recovery time of one relay RS, the operation time of the other relay RS, and the microcomputer
Control data exchanged between COM(T) or between COM(T) and COM(M) (transfer source phone A/
Restore TEL relay RS and transfer destination phone B.
Total time such as transmission time (data for operating TEL relay RS) (usually several milliseconds to several tens of milliseconds)
be. In FIG. 4, the control data transmission time is not shown for simplicity. ), and this time is too long to be ignored in terms of control on the central line C/O side. Therefore, the relay J and resistor R in the main device ME are extremely important for preventing instantaneous interruption of the station line loop during this time.

The end-of-call information of the telephone A/TEL is also transmitted to the main device ME, and the microcomputer COM (M) in the main device ME receives the end-of-call information (t
3-t2) After the time set above the time has elapsed,
Restore Relay J. As a result, the office line loop is no longer held by the resistor R, but at this time, the office line C/O is already connected to the telephone B/TEL, so the office line loop is not released. That is, assuming that the time when relay J is restored is t4, from time t3 to time t4, the central office line loop is held by both the resistor R and telephone B/TEL, and after time t4, the telephone line loop is terminated by telephone B/TEL ( time t5)
Until then, the central office line loop is maintained at telephone B/TEL.

At time t5, when telephone B/TEL ends the call with the central office line C/O and turns on the hook, the telephone switch contact HS opens and the central office line loop is released, and the microcomputer COM
(T) restores relay RS, and
TEL returns to the state before the call.

As is clear from the above explanation, according to the present invention, the secret line secret function and the call route selection function are achieved by one relay RS in the telephone, so it is not necessary to provide a relay dedicated to the secret talk function in each telephone. Because there are no components, the phone requires fewer components and consumes less power.

In addition, when switching the central office line communication path from the transfer source telephone to the forwarding destination telephone, a central office line loop holding circuit (relay J and resistor R) installed in the main device prevents momentary interruption of the central office line loop. Therefore, there is no risk of sending an erroneous signal (break pulse) to the central office line.

As described above, the present invention provides great benefits in terms of system configuration and operation, and its effects are extremely large.

In the embodiment, one office line is used, but the number of office lines does not change the gist of the present invention.

[Brief explanation of drawings]

1 and 2 are block diagrams showing a conventional example, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 4 is a time chart explaining the operation of the embodiment of the present invention. ME...Main device, A/TEL, B/TEL...Telephone, RS...Relay for selecting communication path and secret function, J...Relay for maintaining the office line loop, R...Resistor for maintaining the office line loop.

Claims (1)

[Claims] 1 The main device is equipped with a holding circuit for the central office line loop, and the telephone is equipped with a telephone line selection circuit for selectively connecting the telephone line network to the internal telephone line or the central telephone line. The route selection circuit selects the extension call route in the on-hook state, and when an interrupt operation is performed from another telephone to the telephone that is talking to the central office line, the other telephone transmits the interrupt information to the main unit. A closed loop is formed for the central office line during a call by activating the holding circuit, and a call circuit network in the other telephone is connected to the central office line by a call termination signal from the telephone that is currently speaking. A central line oral transfer system for a button telephone device, in which the internal telephone communication path is switched and connected to the central office line communication path, and the closed loop caused by the holding circuit is released after the switching connection.