JPS63283340A - Power failure telephone call security system for telephone system - Google Patents

Abstract

PURPOSE:To secure a telephone call in a power failure and a telephone call when a power failure occurs in the middle by holding a trunk line at the time of the power failure by using office electricity feeding and transferring a trunk line telephone call to a telephone set for the power failure. CONSTITUTION:If a power failure occurs, a line terminating circuit 3 which operates by being fed with office electricity holds current trunk line communication and then while a main equipment 2 or master equipment connects the trunk line 1 to internal buses 12 and 13 directly, a telephone set for power failure 19 switches its internal extension telephone set circuit 15 to a telephone set circuit 14 which operates by being fed with the office electricity. Then the main equipment 2 or master equipment transfers the held trunk line telephone call to the power failure telephone set 19 to secure the trunk line telephone call during the power failure. Consequently, the construction for extra bus wiring for the installation of a large-capacity backup battery and the power failure telephone set is not required and the power failure telephone set can be installed at an optional point of the internal buses.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a telephone system that time-division multiplexes and transmits a plurality of voice information to an extension bus, and in particular, even if a power outage occurs during a call, The present invention relates to a power outage call guarantee method for a telephone system that allows calls to be held.

"Prior Art" Conventionally, guarantees for making and receiving calls and making calls during a power outage in a telephone system have been performed as follows.

(1) As shown in FIG. 4, a large-capacity backup battery is connected to the main device or parent device, and the entire telephone system is backed up by this large-capacity backup battery in the event of a power outage.

(11) As shown in Figure 5, in the central office line of the telephone system,
By connecting a stand-alone telephone via a power outage changeover switch and directly connecting this telephone to the central office line during a power outage, it is possible to make and receive calls and make calls during a power outage.

"Problems to be Solved by the Invention" However, the above-mentioned system had the following drawbacks.

First, method (i) has the drawback of being able to back up the system only for a short period of time due to the limited battery capacity, and requiring a large-sized, high-capacity backup battery.

In addition, method (11) does not require a backup battery, and during a power outage, it is possible to make and receive calls from the power outage telephone, but ■ Separate bus wiring is required to install the power outage telephone. If a power outage occurs while a telephone call is being made to the central office line from an extension telephone, the telephone call cannot be maintained.

An object of the present invention is to ensure that calls can be made, received, and made during power outages without using large-capacity backup batteries in a bus transmission type telephone system that time-division multiplexes multiple voices and other information and transmits it to an extension bus. The aim is to make power outage countermeasures more economical by making it possible to install telephones that can be used during power outages at any point on an extension bus without using separate bus wiring.

"Means for Solving the Problems" In order to solve the above problems, the present invention connects a plurality of extension telephones to an extension bus, provides an information channel and a control channel on the extension bus, and provides each channel with an information channel and a control channel. In a telephone system that transmits digital signals to and from the office line, the main device or base unit connected to the office line includes a line termination circuit that operates on station power supply and maintains the loop of the office line, and a line termination circuit that transmits and receives signals to and from the extension bus. a power outage detection circuit that detects a power outage; a changeover switch that operates on the local power supply to directly connect one bus of the above to the central office line when a power outage occurs; a control circuit that performs switching control of the changeover switch; A loop detection circuit that operates on local power supply is provided in the power outage telephone to detect hook information of a power outage telephone connected to the extension bus and used in the event of a power outage. A telephone circuit, a power outage detection circuit, a changeover switch that uses internally stored power to switch the extension telephone circuit to a telephone circuit operated by the station power supply in the event of a power outage, and a control circuit that controls switching of the changeover switch, If a power outage occurs while a telephone is being used to make a call on a central office line, the main device or base unit puts the central office line on hold and directly connects the central office line to the internal bus, while the power outage telephone , the telephone circuit is switched from the extension telephone circuit to the telephone circuit operated by the central office power supply, and the telephone line held on the main device or base unit is transferred to the power outage telephone, thereby maintaining calls during a power outage. shall be.

"Operation" According to the present invention, when a power outage occurs, the line termination circuit operated by the station power supply suspends the station line communication in progress, and then the main device or base unit connects the station line directly to the extension bus, and The power outage telephone switches its internal extension telephone circuit to a telephone circuit that operates on local power supply. Then, by transferring the central office line call on hold from the main device or base unit to the power outage telephone, the central office line telephone call is guaranteed in the event of a power outage.

Compared to conventional technology, the present invention: ■ does not require a large-capacity backup battery; ■ does not require construction of separate bus wiring to install a power outage telephone; ■ installs a power outage telephone at any point on an extension bus. The advantage is that it can be installed.

"Example" Hereinafter, the present invention will be described in detail with reference to the drawings.

First, an example of a telephone system in which an information channel (referred to as B ch) and a control channel (referred to as D ah) are transmitted separately will be described.

FIG. 1 is a detailed diagram illustrating the present invention, in which l is a central office line, 2 is a main device or base unit that controls the entire telephone system, and the central office line l and extensions, and 3 is a central station. A line termination circuit operated by power supply, 4 a switching circuit for exchanging office line information and extension line information, 5 an extension interface circuit, 6 a control for directly connecting the office line l to an extension bus 12.13 described later, and system operation. 7 is a circuit in the main unit or main unit 2 and an extension bus 12.1.
3 is a power supply that supplies power, 8 is a power outage detection circuit that detects a power outage,
9. IO is a changeover switch operated by the local power supply that directly connects the office line l to the extension bus 12.13, and 11 is a bypass line that directly connects the office line l and the extension bus 12.13 in the event of a power outage.

Of the extension buses 12 and 13, extension bus 12 is a Bch bus that transmits Bch in digital signal format, and extension bus 1.
3 is a Dch bus for transmitting Dch.

In addition, 14 is a telephone circuit that can operate with local power supply during a power outage;
15 is an extension telephone circuit that operates when power is supplied from the main device or base unit 2 via the Dch bus, 16 is a power outage detection circuit that detects a power outage, and 17 is a power outage detection circuit that detects a power outage.
Telephone circuit 14 and extension telephone circuit 15 that operate with central power supply
This is a control circuit that performs switching.

18 connects the Bah bus 12 to the telephone circuit 14 in the event of a power outage.
, a changeover switch that connects to the extension telephone circuit 15 when the power is on, 19 a power outage telephone, 20 a loop detection circuit that detects the hook information of the power outage telephone 19 and operates on central power supply, and 21 stores power when the power is on. , a capacitor that supplies power to operate the selector switch 18 during a power outage, and 22 an extension telephone.

Next, the operation of this embodiment will be explained.

FIG. 2 is a diagram illustrating an operation during a transition from a telephone call in an energized state to a power outage.

If a power outage occurs while the extension telephone 22 is in the middle of a telephone call,
The power failure detection circuit 8 of the main device or base unit 2 notifies the control circuit 6 of the power failure. The control circuit 6 instructs the line termination circuit 3, which operates with the station power supply, to hold the station line 1, and at the same time starts the timer T.

The control circuit 6 also controls the Bch
The bus 12 and Dch bus 13 are connected to the extension interface circuit 5.
At the same time, the central office line l is controlled to be directly connected to the Bch bus 12 by the changeover switch 9°lO.

A power outage detection circuit 16 in the power outage telephone 19 monitors the voltage of the Dch bus 13 and notifies the control circuit 17 when a power outage is detected. The control circuit 17 that has received the power failure notification controls the changeover switch 18 to switch the connection of the BCh) 14 is directly connected to the central office line l.

In addition, when the changeover switch 18 is configured with a latching relay, the changeover can be performed using the electric power of the capacitor 21. Alternatively, if the changeover switch 18 is configured with a relay, the capacitor 21 can be omitted if the changeover (recovery) is automatically performed when external power is lost.

In this state, when the caller moves from the extension telephone 22 to the power outage telephone 19 and takes the power outage telephone 19 off-hook,
It becomes possible to make telephone calls using the power outage telephone 19. The loop detection circuit 20 detects the off-hook of the power outage telephone 19,
When the control circuit 6 is notified, the control circuit 6 stops the timer T. Until timer T times out (for example, 3 minutes),
If the power outage telephone 19 does not go off-hook, the control circuit 6 forcibly disconnects the office line l.

When the power outage telephone 19 ends the call and goes on-hook, the loop detection circuit 20 detects loop breakage and notifies the control circuit 6. The control circuit 6 controls the line termination circuit 3 and
cut. In this way, the process when a power outage occurs during a call is completed.

Next, FIG. 3 is a diagram showing the operation when transitioning from power outage to energization during a power outage call.

Power outage detection circuit 8 detects energization and notifies control circuit 6 of the detection. The control circuit 6 instructs the line termination circuit 3 to hold the central office line 1, controls the changeover switch 9 and lO, and switches the Bch
Disconnect bus 12 from central line l.

Since the power outage telephone 19 is disconnected from the central office line l, it is reset. Next, the control circuit 6 switches the changeover switch IO
to connect the Bch bus 12 and the Dch bus 13 to the extension interface circuit 5. Main device or base unit 2
starts supplying power to each extension telephone 22 and power outage telephone 19 via the Dch bus 13.

Each extension telephone 22 performs initial settings upon detecting energization. Further, when the power outage telephone 19 detects power supply, the control circuit 17 performs initial settings, controls the changeover switch 18,
The connection to the Bah bus 12 is switched from the telephone circuit 14 that operates on local power supply to the extension telephone circuit 15. When synchronization of the Bch bus 12 is established, each telephone 19, 22 transmits a signal indicating completion of initial setting and establishment of synchronization to the main device or base unit 2. After receiving the signal, the main device or base unit 2 allocates the Bch and enables communication between the power outage telephone 19 and the central office line 1. The above is the operation at the time of transition from power outage to power on.

Although the above embodiment has been described as an example of a system in which Dch and Bch are separated, Dch and Bch are time-division multiplexed, and the extension bus is divided into 4 lines with an up line (T line) and a down line (R line).
A similar method can be applied to wire transmission or so-called Bing-Bong two-wire transmission. In addition, the central office line is
A similar method can be applied to the digital user network interface (■ interface) according to the CCITT recommendation.

"Effects of the Invention" As explained above, the present invention utilizes the local power supply to put the central line on hold during a power outage and transfers the central line call to a power outage telephone, thereby making it possible to handle calls during a power outage and power outages during calls. Since the system can guarantee calls at any time, there is no need for large-capacity backup batteries, making the system more economical.

Another advantage is that the power outage telephone can be connected to any point on the extension bus without using a separate line.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a diagram illustrating the operation from power on to power outage, which best represents the features of this embodiment, and Fig. 3 is a diagram from power outage to power outage. FIGS. 4 and 5, which are diagrams for explaining the operation at the time of transition to energization, are block diagrams showing an example of the configuration of a conventional telephone system. 1 is the central office line, 2 is the main device or parent unit, 3 is the line termination circuit, 4 is the switching circuit for exchanging central line information and extension information, 5 is the extension interface circuit, and 6 is the control for directly connecting the central office line to the extension bus. and a control circuit that controls the operation of the system; 7 is a power supply that supplies power to the circuit of the main device and the extension bus; 8 is a power outage detection circuit that detects a power outage; 9.10 is a changeover switch that directly connects the office line to the extension line; 11 is a bypass line that directly connects the office line and the extension line, 12.13 is an extension bus, 12 is an information channel (Bah) bus, 13 is a control channel (Dch) bus, 14 is a telephone circuit that operates on central power supply, 15 is an extension telephone circuit; 16 is a power outage detection circuit that detects a power outage; 17 is a control circuit that controls switching between the telephone circuit 14 and the extension telephone circuit 15; 18 is a changeover switch that connects the Bch bus 12 to the telephone circuit 14; 2 is a power outage telephone; 20 is a loop detection circuit for detecting hook information of the power outage telephone 19;
1 is a capacitor, and 22 is an extension telephone.

Claims (1)

[Scope of Claim] A telephone system in which a plurality of extension telephones are connected to an extension bus, an information channel and a control channel are provided on the extension bus, and digital signals are transmitted to each channel, comprising: Inside the device or main unit, there is a line termination circuit that operates on station power supply and maintains a loop of the station line, an extension interface circuit that exchanges signals with the extension bus, a power outage detection circuit that detects a power outage, and a power outage detection circuit that detects power outage. At this time, a changeover switch that connects the extension bus directly to the central office line that operates on the local power supply, a control circuit that controls switching of the changeover switch, and hook information of a power outage telephone connected to the extension bus and used in the event of a power outage are detected. A loop detection circuit that operates on station power supply is provided in the power outage telephone, in addition to the extension telephone circuit, the power outage telephone includes a telephone circuit that operates on station power supply, a power outage detection circuit, and a loop detection circuit that operates on station power supply, and a loop detection circuit that operates on station power supply, and that uses internally accumulated power to A changeover switch for switching a telephone circuit to a telephone circuit operated by the central office power supply, and a control circuit for controlling switching of the changeover switch, are provided, and if a power outage occurs while a telephone call is being made on the central office line using the extension telephone, the above-mentioned After putting the central office line on hold, the main device or base unit directly connects the central office line to the extension bus, while the power outage telephone switches from the internal telephone circuit to the telephone circuit that operates on the central office power supply, and A power outage call guarantee method for a telephone system, characterized in that calls are maintained during a power outage by transferring a central office line on hold in a main device or base unit to the power outage telephone.