JP6412452B2 - 2 household intercom system - Google Patents

Description

  The present invention relates to a two-household intercom system, and more particularly, to a two-household intercom system including a wireless master unit that can respond to calls from an entrance cordless handset by wireless communication.

There is a two-household intercom system with two base units. In this intercom system, the entrance cordless handset is provided independently for each household, or the call buttons for the parent and child households are provided independently in a common housing, and the living room master is installed in each household. . In such a two-household intercom system, the room master units are configured to be able to talk to each other. For example, the room master units are connected via a transmission line (see, for example, Patent Document 1).
There is also an intercom system equipped with a portable wireless master unit that can respond to calls from the entrance slave unit in addition to the living room master unit. This is because wireless communication is carried out between the living room parent device and the wireless parent device, and a call can be made between the entrance child device and the wireless parent device via the living room parent device (for example, Patent Documents). 2).
On the other hand, there is a TDMA system as a wireless communication system. This TDMA system is widely used in mobile phones, wireless telephones, and the like because it can communicate in real time without collision by including a signal in a slot divided by a guard time in time (see, for example, Patent Document 3).

JP 2000-278413 A JP 2011-176664 A JP-A-2005-286406

In the TDMA scheme, a synchronization signal is periodically transmitted from the base station to the wireless device in order to achieve frame synchronization between the base station and the wireless device. Therefore, when this TDMA system is used for communication between the living room master and the wireless parent machine, a synchronization signal generator is provided on the living room parent side for synchronization, and the synchronization signal is periodically transmitted to the wireless parent machine. Need to be sent to.
However, when this method is applied to a two-household intercom system, both living room base units are installed at relatively close positions, so that a frame drift occurs due to a clock error generated between both synchronization signal generators. However, there is a problem that slot interference occurs with time.

  Therefore, in view of such problems, the present invention provides a two-household intercom system in which frame drift does not occur even if a wireless master unit adopting the TDMA system is provided for both living room master units. The purpose is that.

In order to solve the above-mentioned problems, the invention of claim 1 includes an entrance cordless handset provided at a front door and provided with a parent household call button and a sub household call button, and two types for answering a call from the entrance cordless handset. In a two-household intercom system having a living room base unit and connected to each other by a wired connection, the room base unit has a wireless communication unit and can communicate with the wireless base unit using the TDMA system. One living room base unit uses a transmission line formed by wire connection to output a clock signal to the other living room base unit, and a clock correction unit that corrects its own clock when receiving the clock signal When, and a parameter storage unit for storing parameters of the received clock signal, upon receiving a call from the entrance door station, not from the called room master station of the calling room master It transmits a clock signal to the clock correction means, when the interruption clock signal, characterized in that it continues its own clock correction based on the information stored in the parameter storage unit.
According to this configuration, since the clock frequency of the other room parent device is corrected by the clock signal of one room parent device using the transmission path disposed between the room parent devices, both of them can be configured with a simple structure. Thus, it is possible to prevent radio interference due to drift of the frame when the base unit communicates with the wireless base unit.

Further, even if the clock signal transmitted from the other room master is interrupted, the clock correction can be continued based on the information in the parameter storage unit. Therefore, transmission of the clock signal via the transmission path may be irregular, and power saving can be achieved.

In addition , since the synchronization is achieved by using the call operation as a trigger, even if the clock signal is transmitted irregularly, the synchronization can be surely performed at a timing with a high probability of using the wireless master unit.

  According to the present invention, since the clock frequency of the other room parent device is corrected by the clock signal of one room parent device, both clocks can be synchronized, and when the room parent device communicates with the wireless parent device. In addition, radio wave interference due to frame drift does not occur.

It is a schematic block diagram which shows an example of the 2 household intercom system which concerns on this invention. It is a principal part block diagram of a living room main | base station.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention are described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of a two-household intercom system according to the present invention, in which 1 is an entrance child machine, 2 is a living room parent machine (child household parent machine 2a, parent household parent machine 2b), and 3 is a wireless parent machine. Machine. The entrance child device 1 has a child household calling button 1a and a parent household calling button 1b, and is connected to each living room parent device 2 via transmission lines L1 and L2. In addition, the living room master units 2 are also connected to each other via a transmission line L3 to enable calling / calling between the two.

The child household parent device 2a and the parent household parent device 2b have a basic configuration (not shown) as an interphone such as a call button for responding to a call from the front door child device 1, a microphone and a speaker for calling, etc. In addition, a function of communicating with the wireless master device 3 is provided.
However, the internal frequency of the child household parent device 2a is configured to synchronize based on the clock signal generated by the parent household parent device 2b.

  The configuration and operation in which the child household base unit 2a is synchronized with the parent household base unit 2b are as follows. FIG. 2 is a circuit block diagram showing a configuration for synchronizing frequencies, and shows a main part of the child household parent device 2a. As shown in FIG. 2, the child household base unit 2a includes a clock oscillation circuit 21, a PLL circuit 22, a frequency adjustment circuit 23 that adjusts the oscillation frequency of the clock oscillation circuit 21, and a clock signal parameter to be described later. A parameter storage unit 24 that stores information, a TDMA communication unit 26 that performs communication with the wireless master unit 3 by the TDMA method, a master CPU 27 that controls each circuit of the child household master unit 2a, and the like are provided. Is a synchronization signal generator for generating a synchronization signal.

  The parent household parent device 2b has the same configuration as the child household parent device 2a except that the parent household parent device 2b does not have the parameter storage unit 24. The clock oscillation circuit 21, the PLL circuit 22, the frequency adjustment circuit 23, the TDMA communication unit 26, A master CPU 27 and a synchronization signal generator 26a for controlling each circuit of the household master 2b are provided. The parent CPU 27 of the parent household parent device 2b operates as a clock signal output means for outputting a clock signal to the child household parent device 2a.

The child household parent device 2a and the parent household parent device 2b are connected via a transmission line L3 as a transmission path for two-way calling / calling. The parent household parent device 2b uses the transmission line L3. The generated clock signal is transmitted to the child household base unit 2a. The transmitted clock signal is received by the PLL circuit 22, and a synchronization signal based on the clock signal received from the PLL circuit 22 to the parent CPU 27 is output.
In response to this synchronization signal, the master CPU 27 operates as a clock correction means, controls the frequency adjustment circuit 23, adjusts the frequency, and synchronizes the clock. As a result, the internal clock can be synchronized even if there is an error between the frequency of the clock oscillation circuit 21 and the oscillation frequency of the clock oscillation circuit (not shown) of the parent household master unit 2b.

  The master CPU 27 stores the parameters generated for controlling the frequency adjustment circuit 23 in the parameter storage unit 24. As a result, the frequency adjustment circuit 23 can be controlled based on the information stored in the parameter storage unit 24 even when the transmission line L3 is used for a call or the like and the clock signal is not transmitted from the parent household device 2b. , Can keep synchronized. Therefore, even if transmission of the clock signal from the parent household parent device 2b is irregular, it is possible to continue the synchronization of both.

In this way, the clock frequency of the child household parent device 2a is corrected by the clock signal of the parent household parent device 2b using the transmission line L3 disposed between the child household parent device 2a and the parent household parent device 2b. Therefore, both clocks can be synchronized with a simple configuration. Since the clocks of the parent household device 2b and the child household device 2a can be synchronized, radio communication due to frame drift does not occur when communicating with the wireless parent device 3, and the wireless parent device 3 is always present. Can be used satisfactorily.
Further, even if the clock signal transmitted from the parent household master unit 2b is interrupted, the clock correction can be continued based on the information in the parameter storage unit 24, so that the clock signal transmission via the transmission line L3 may be irregular, Power saving can be achieved.

In the above embodiment, the parent household parent device 2b is set as the master and the child household parent device 2a is synchronized with the clock of the parent household parent device 2b. That is, the child household parent device 2a may be operated as a master. Furthermore, without setting the master, both the room master units 2 have the same function, that is, the clock signal transmission function and the clock signal reception function, and further the parameter storage unit 24, so that the clock signal can be bidirectionally transmitted. May be carried out.
With such a configuration, for example, when a call operation is received from the front cordless handset 1, a clock signal can be transmitted and synchronized from the called room base unit 2 to the room base unit 2 without a call. Even if the signal transmission is irregular, it is possible to reliably synchronize at a timing with a high probability of using the wireless master device 3, and to further save power.
Furthermore, at the time of initialization after power-on, it is possible to synchronize by transmitting the clock of the room master unit that has been previously powered on in consideration of clock stabilization.

  1 .. Entrance child machine, 1a .. Child household call button, 1b .. Parent household call button, 2 (2a, 2b) ..Room parent machine, 3 .. Wireless parent machine, 21 ..Clock oscillation circuit, 22 ..PLL circuit, 23..Frequency adjustment circuit, 24..Parameter storage unit, 26..TDMA communication unit, 26a..Synchronization signal generation unit, 27..Master CPU (clock signal output means, clock correction means) .

Claims (1)

There is an entrance cordless handset installed at the entrance and provided with a parent household call button and a child household call button, and two room master units for responding to calls from the entrance cordless handset. In a two-housed intercom system that is wired,
Wherein each room master station is a can communicate by a wireless master unit and the TDMA system includes a wireless communication unit, the two room master station, the other using the transmission path formed by the wired connection It has a clock output means for outputting a clock signal to said room master station, and a clock correcting unit that corrects its own clock upon receipt of the clock signal, and a parameter storage unit for storing parameters of said clock signal received ,
When a call is received from the entrance slave unit, a clock signal is transmitted from the called room master unit to the room master unit without a call,
When the clock signal is interrupted, the clock correction unit continues its clock correction based on the information stored in the parameter storage unit .

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