JPS63203048A - 4-wire multi-party line telephone system - Google Patents

Abstract

PURPOSE:To attain multi-party communication by providing a means or the like receiving a multi-frequency code dial signal for plural number of times so as to call plural optional called parties in plural 4-wire telephone sets selectively connected to a 4-wire multi-party line. CONSTITUTION:Four-wire telephone sets TEL10-40 each consist of a transmission circuit XMT2, a reception circuit RCV3 and a control circuit CTL4 or the like and the RCV3 can receive a multi-frequency code MFC dial signal for plural number of times. If a communication request takes place from the TEL10 to the TEL40 further during the communication in the TEL10 and the TEL20, the TEL10 sends an MFC signal corresponding to the TEL40 to a transmission line LA5. The MFC signal is received by the RCV 3 via the reception circuit LB5 at the side of the TEL40, and the circuit CTL4 discriminates that itself is a called party, a bell rings and the TELs 10, 20, 40 are in the state of 3-party communication by the called party reply by the TFL40. Thus, plural optional called parties among TELs in multidrop connection to the 4-wire line 5 are subject to selective call and multi-party communication is attained among the TELs.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a 4-wire multi-party telephone system, and particularly to a 4-wire multi-party telephone system that can select and call a plurality of 4-wire telephones in a multi-party system. Concerning party telephone system.

[Conventional technology]

Traditionally, this type of 4-wire multiparty telephone system consists of a multi-drop connection of 4-wire telephones to a set of transmitting and receiving 4-wire lines, with each 4-wire telephone having an individual, identifiable address. is assigned. That is, the calling station dials the address of the called station that is not called, and sends this dial information to the transmission line of the four-wire line.

At this time, all other 4-wire telephones connected to the 4-wire line in a multi-drop manner receive this dialing information, and if it matches their own address, they recognize that they are the called station and connect their own 4-wire telephones. The phone was ringing the bell. The control circuit connects the line when the called party answers, allowing a conversation between the calling party and the called party. Normally, multi-frequency code MF C (Multi Frequency Code) is used to transmit dial information, that is, signal information such as address and off-hook.
Code) is used.

[Problem that the invention seeks to solve]

4 using the conventional non-multiplexed dedicated line mentioned above.
In wire-based multi-party telephone systems, when a call is being made between one set of calling parties, even if a call request occurs on a four-wire telephone set other than this one set, the caller or called party It cannot be. Therefore, this call request is dealt with by multiplexing dedicated lines or by making interrupts possible.

However, one set of callers who is already on a call has the disadvantage that even if a call request is made to a 4-wire telephone set other than the other party's phone, they will not be able to talk to the other party unless the call is terminated. .

[Means for solving problems]

The 4-wire multi-party telephone system of the present invention is a multi-drop system that connects a plurality of 4-wire telephones each equipped with a transmission/reception circuit for a dial signal line, a control circuit for controlling the transmission/reception, and an audio interface circuit to a 4-wire line. A four-wire multi-party telephone system is provided in which each of the four-wire telephones is provided with means for receiving the dialing signal a plurality of times.

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

FIG. 1 is a block diagram showing one embodiment of the four-wire multiparty telephone system of the present invention.

In this embodiment, a plurality of 4-wire telephones (hereinafter referred to as the device) are multi-drop connected to a 4-wire line 5, and the device includes 1 dial signal, 1 line control signal transmission circuit (hereinafter referred to as XMT), 2. Receiving circuit (hereinafter referred to as RCV) 3 and its control circuit (hereinafter referred to as CTL) 4
The four-wire line 5 includes a transmitting line (hereinafter referred to as LA) and a receiving line (hereinafter referred to as LB). Note that RCV3 is M
It has a function of receiving FC dial signals multiple times.

In other words, each LA on the XMT2 side with a total of 0 is a branch circuit (
Below BR) 1 through 'IF, 120°3017) RC
V3. It is connected to XMT4, and is further connected to RCV3 of the device 40 as a LB on the device 40 side. Also, L on the 40 side
A is connected to RCV3°
Connected to RCV3 of O.

Next, the operation of this embodiment will be explained.

When the station IO makes a call to call the station 20, a total of 0 XMT2'IF and MFC dial signals corresponding to L20 are transmitted to the LA. At the station 20, the RCV 3 receives the MFC dial signal via the BRI, compares it with the address preset in the CTL 4, determines that the station 20 is the called party, and calls the local TF, L20. A bell (not shown) is rung. When the called party responds, the
A call circuit between 20 people is set up and a call begins. Note that the MF
The C-dial signal is also received by each RC3 (30.4(1)), but each CTL4 also determines that it is not the called party as a result of address verification, so each bell is not rung.

During a call between upper devices I0 and 20, if a request for a call to, for example, device 40 occurs at device I0,
O sends an MFC dial signal compatible with location 40 to LA. This MFC dial signal is on the 40 side (7) L'B
The CTL 4 determines that the caller is the called party and rings a bell (not shown). IO is placed by the called party's response at 40.

During the period of 20.40, there will be a three-party call state.

It is clear that the present invention can be applied even when a four-wire multi-party line is configured as a multi-party line using a PCM line or a voice line.

〔Effect of the invention〕

As explained above, the present invention allows selective calling of any number of called parties from among a plurality of 4-wire telephones connected to a 4-wire multi-party line. This has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the four-wire multiparty telephone system of the present invention.

Claims (1)

[Claims] A 4-wire multiparty telephone system in which multiple 4-wire telephones, each equipped with a transmission/reception circuit for dialing signals and line control signals, a control circuit for controlling the transmission/reception, and an audio interface circuit, are multi-drop connected to a 4-wire line. The four-wire multi-party telephone system is characterized in that each of the four-wire telephones is provided with means for receiving the dial signal a plurality of times.