JPH07110029B2 - Communication terminal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a communication terminal device used in a communication system in which at least one line is used by a plurality of communication devices.

[Prior Art] Conventionally, as a communication system of this type, for example, ISDN (Inte
grated Services Digital Network) system is known. This ISDN line has three communication channels, each line consisting of two data channels (B channel) and one control channel (D channel), to which a maximum of eight terminals are connected. If the communication channel is free, communication can be performed in response to a communication request from each terminal.

[Problems to be Solved by the Invention] When a plurality of terminals use a small number of lines as in this ISDN system, even if one terminal tries to communicate, communication cannot be performed when the lines are in use. At this time, there is a problem that it is not possible to know whether communication is possible unless the communication request is actually made each time.

[Means and Actions for Solving Problems] In the present invention, since the notification means notifies that the line is available when the communication request is made, the operator can easily request the communication. You can know the possible timing.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to the drawings. In this embodiment, a digital telephone connected to the ISDN system will be described as an example.

1 to 4 are diagrams showing the present embodiment, and FIG. 1 is a connection diagram in which the communication terminal device of the present embodiment is connected to an ISDN network. 1 is a network terminating device that is a network termination, 2 is a bus line that connects 1 network terminating device and a plurality of terminal devices, 3 is a subscriber line that connects an ISDN switch and 1 network terminating device, 4,8,10,11 are general digital telephones, 5,9 are digital facsimile devices, 6 is a telex device, and 7 is a digital telephone according to this embodiment. FIG. 2 is an external view of the digital telephone of this embodiment. In FIG. 2, 21 is a digital telephone body,
22 is a handset, and 23 is a key button for inputting a telephone number and the like. FIG. 3 is a block diagram showing the configuration of this embodiment. In FIG. 3, 31 is a digital telephone body, 32
Is a central processing unit, 33 is an EPROM, 34 is a RAM, 35 is an I / O controller, 36 is a codec, 37 is a communication chip, 38 is a key button, 39 is a handset, and 40 is an ISDN line.

Next, the operation of the above embodiment will be described.

FIG. 4 is a flow chart showing the operation of the above embodiment. In this embodiment, one D channel and two B channels
The book is a 2B + D ISDN line. First, all B in Figure 4 S1
When the channel is in use and the call cannot be made, the operator dials the special code "99" to register the B-CH availability notification function in S2. The operator registers the B-DH availability notification from the terminal device. In the embodiment, the device registered with the B-CH empty notification function monitors the sequence of the D channel signal in S3 to determine whether the B1 channel is empty.
In S4, the same method is used to determine whether the B2 channel is free. At S3 and S4, when it is confirmed that the B channel is free, ringing is sounded in S5 and the calling operator is called. Next, in S6, it is confirmed that the calling operator responds by off hook. If the operator's response is confirmed in S6, a dial tone is emitted in S7 to notify the operator that the call may be made, and the operator performs the call operation. Next, in S8, a normal call operation is started.

In the above embodiment, when all the B channels were in use, the operator was informed that the B channels were vacant. However, when the B channel became vacant, the device automatically recalled and the other party's line was connected. A method of notifying the operator on the own side (calling side) may be used.

As described above, when the B channels are all in use, the device monitors the usage status of the B channels at the request of the operator and notifies the operator when the B channels are available. The operator's operation can be reduced and the line efficiency can be improved.

[Effect] As described above, according to the present invention, the line can be used efficiently and the operation of the operator can be reduced.

[Brief description of drawings]

FIG. 1 is a connection diagram in which the communication terminal device of this embodiment is connected to an ISDN network, and FIG. 2 is an external view of the digital telephone of this embodiment. FIG. 3 is a block diagram showing the configuration of this embodiment, and FIG. 4 is a flow chart for explaining the operation of this embodiment. 1 is a digital telephone main body, 2 is a central processing unit, 3 is an RO
M, 4 RAM, 5 input / output control device, 6 codec, 7
Is a communication chip, 8 is a key button, 9 is a handset, 10
Is an ISDN bus line.

Claims (1)

[Claims] 1. A communication terminal device used in a communication system in which at least one line is used by a plurality of communication terminal devices, detecting means for detecting a state of the line, and instructing means for instructing a communication request, A communication terminal device, comprising means for notifying that the line is available when the line is available on condition that a communication request instruction is given.