JPH1023570A - Isdn terminal accommodation device for leased line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leased line ISDN terminal accommodation device which connects an ISDN terminal to a leased line. SOLUTION: An adapter 2a is connected between the ISDN terminal 1a and leased line LC. An ISDN terminal and an adapter of the same constitution an them are arranged opposite across the leased line LC. A Dch protocol control part 6a extracts control information from D-channel data separated by a data separation part 4a. A link pattern generation part 7a generates and sends out a link pattern to the opposite adapter and a link pattern detection part 10a detects a link pattern received in response. Said control information is carried with a time slot of a B1 or B2 channel and user data are sent out to the opposite adapter as they are. Data from the opposite adapter are separated by a data separation part 12a and sent over the D channel by the Dch protocol control part 6a when control information or sent directly to a data multiplexing part 5a when the user data, and those are multiplexed on a time-division basis and sent out to the ISDN terminal 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dedicated line ISDN terminal accommodating apparatus for connecting an ISDN (Integrated Services Digital Network) terminal to a dedicated line.

[0002]

2. Description of the Related Art A network called ISDN is conventionally known as a digital network for transmitting various media such as facsimile, still image and moving image in addition to voice at high speed. The ISDN realizes a many-to-many line connection between a large number of subscribers by circuit switching, and each subscriber performs a line connection and performs communication only when communication is required. Here, as one of the communication interfaces in ISDN, there is a method in which communication between subscriber terminals is realized using three channels called B1, B2, and D channels. Incidentally, this communication interface is called 2B + D.

[0003] Of these channels, both the B1 channel and the B2 channel are information channels for transmitting voice and various data, and both have a channel speed of 64k.
bps (kilobits per second). In contrast,
The D channel is a signal channel used for line control at the time of transmission and reception for communication performed on the B1 and B2 channels, and the channel speed is set to 16 kbps. A terminal suitable for such an interface is called an ISDN terminal.

On the other hand, apart from ISDN, 128 kbps
There is a communication form called "dedicated line" such as super digital having a line speed of. In this embodiment, the leased line presupposes one-to-one communication, and is used, for example, for an extension telephone between a head office and a branch of a company. In the case of using such a dedicated line, since the communication partner is predetermined, it is not necessary to dial the telephone number of the other party, and if the mutual connection is established, the data can be drained out. Therefore, in the communication using the dedicated line, the control channel existing in the ISDN is unnecessary, and the communication between the terminals is realized using only the information channel. As can be seen from the above, the terminal connected to the dedicated line communicates only with the information channel, and a dedicated line terminal different from the ISDN terminal is used.

Here, the following are conceivable advantages of using the dedicated line. In other words, ISDN and the like generally adopt a pay-as-you-go system in which a fee is charged in proportion to the usage time of the line. In applications where the line is occupied for a long time, the line usage fee becomes enormous. There is also a possibility. On the other hand, the dedicated line has the restriction that the communication partner is fixed, but it is only necessary to pay a fixed usage fee that does not depend on the line usage time, and always connect the line without worrying about the connection time Can be. Therefore, when a line is expected to be used for a predetermined time or more, it can be said that it is advisable to use a dedicated line instead of the ISDN.

[0006]

As described above, a subscriber needs to purchase a terminal corresponding to a line to be used. That is, if ISDN is used, ISD
When N terminals are connected and a dedicated line is used, it can be said that a dedicated line terminal needs to be connected. However, IS
Even when using a DN, when the use status of the line changes due to work circumstances, etc., the line connection time increases, and the cost can be reduced by using a dedicated line rather than using ISDN. May occur. In such a case, in the conventional case, when a contract for switching from the ISDN to the leased line is made, it is necessary to replace the terminal with that for the leased line, and the ISDN terminal used up to now is wasted. Problems arise.

[0007] On the other hand, although a dedicated line is used for the time being, there are cases where it is desired to switch to ISDN in the future. In such a case, in the past, for the time being, a dedicated line terminal was purchased and connected to the dedicated line, and when a contract for switching to ISDN was made, a new I
Since the SDN terminal must be purchased again, the dedicated line terminal is wasted this time.

The present invention has been made in view of the above points, and has as its object to provide an IDN having a circuit switching function of ISDN.
Dedicated line ISDN for connecting SDN terminals to dedicated lines
A terminal accommodation device is provided. More specifically, the present invention, when viewed from an ISDN terminal, simulates that the terminal is connected to an ISDN instead of a dedicated line, thereby enabling an ISDN terminal to be connected to a dedicated line. It is intended to provide an ISDN terminal accommodation device.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 provides an ISDN terminal which performs time-division multiplexing of a control channel and an information channel to perform communication using the information channel. An exclusive line ISDN terminal accommodating apparatus for accommodating an exclusive line to be used, wherein the ISDN terminal
A first extracting unit that extracts control information used for controlling the information channel from the control channel, among the time-division multiplexed data sent from the terminal, the control information extracted by the first extracting unit, First multiplexing means for time-division multiplexing the user data carried on the information channel among the division multiplexed data on the information channel and sending the data to the dedicated line; A second extraction unit that extracts, from the information channel, the control information carried on the information channel of the line data, among the line data sent via the dedicated line, and the second extraction unit The control information is loaded on the control channel, and the line data is time-division multiplexed with the user data loaded on the information channel, so that the IS
And a second multiplexing means for transmitting to the DN terminal.

According to a second aspect of the present invention, in the first aspect of the invention, a plurality of the information channels are provided,
Channel selecting means for selecting an empty channel from these information channels, wherein the second extracting means extracts the control information from the information channel on the empty channel side, and the first and second multiplexing means Is characterized in that the control information and the user data are time-division multiplexed using the information channel on the free channel side.

According to a third aspect of the present invention, in the first or second aspect, a pattern generating means for generating a link pattern used for establishing or disconnecting a link between the ISDN terminal and the destination terminal. Pattern detection means for detecting the link pattern sent from the pattern generation means on the destination terminal side, and, as a response to the link pattern sent from the destination terminal side, the link pattern as the information channel And a transfer means for changing the position.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the super digital service, the frame format of layer 1 is the same as that of ISDN. Therefore, in the device according to the present embodiment, B
Using time slots of one channel and B2 channel,
These are directly transmitted as two information channels on a dedicated line. FIGS. 1 and 2 are block diagrams showing a configuration of a dedicated line ISDN terminal accommodating apparatus according to the embodiment and terminals and the like connected thereto. In these figures, reference numerals 1a and 1b denote generally used ISDN terminals.

Each of the adapters 2a and 2b is a dedicated line ISDN terminal accommodating apparatus according to the present invention, and is physically disposed near the ISDN terminals 1a and 1b, respectively. The configurations of these adapters are all the same, and are arranged to face each other via a dedicated line LC. Here, actually, the dedicated line L
C also passes through a station existing in the public network, but logically, the dedicated line passes through the public network, and thus is not shown in the figure, and is drawn as if it were directly connected. In these figures, the symbol T indicates sending, and the symbol R indicates receiving.

The ISDN terminal 1a and the adapter 2a or the ISDN terminal 1b and the adapter 2b are connected by cables 3a and 3b for transmitting the B1, B2 and D channels by time division multiplex, respectively. . That is,
Communication is performed between the ISDN terminal and the adapter at a line speed of, for example, 192 kbps according to the same protocol as the ISDN.

Next, each part constituting the adapters 2a and 2b will be described. In the following, only the adapter 2a will be described, but each component of the adapter 2b has the same function as each component of the corresponding adapter 2a.
The data separation unit 4a separates the time-division multiplexed line data sent from the ISDN terminal 1a into D channel, B1 channel, and B2 channel at the timing instructed by the Dch protocol control unit 6a to be described later and outputs the data. I do.

The data multiplexing unit 5a transmits B1, B1 transmitted from the communication partner (adapter 2b) via the dedicated line LC at the timing specified by the Dch protocol control unit 6a.
Each data of the B2 channel is transmitted to the Dch protocol controller 6
a is time-division multiplexed together with the control information of the D channel transmitted by a.
Send to SDN terminal 1a.

The Dch protocol control unit 6a has an ISDN
In order to simulate a network, the D channel to the ISDN terminal 1a is controlled.
It supervises each part provided in. The Dch protocol control unit 6a monitors the data of the D channel separated by the data separation unit 4a, and transfers control information and the like for managing the B channel to any of the free channels B1 and B2. I do. For this purpose, the Dch protocol control unit 6a manages the state of whether each of the channels B1 and B2 is in use or empty.

When the Dch protocol control unit 6a detects the telephone number of the other party as control information, this is unnecessary for communication using a dedicated line, and is ignored. In addition to these, Dch
The protocol control unit 6a performs processing such as detecting an instruction to connect or disconnect a line from the information of the D channel separated by the data separation unit 4a, sending a message to the adapter 2b, and the like. Details will be described in the description of the operation.

Under the control of the Dch protocol control unit 6a, the link pattern generation unit 7a generates a special bit pattern called a link pattern that determines the timing of connection / disconnection of a line. The link pattern may be a bit pattern that does not normally flow in the B1 channel or the B2 channel. In the present embodiment, a predetermined cyclic code such as a PN pattern (pseudo random pattern) is used as the link pattern. In this embodiment, the link pattern generators 7a and 7b generate the same link pattern.
Different link patterns may be generated.

The switch 8a selects one of the B1 channel data from the data separation unit 4a, the output of the Dch protocol control unit 6a, and the output of the link pattern generation unit 7a under the instruction of the Dch protocol control unit 6a. Then, the data is sent to the data multiplexing unit 11a described later. At the time of initialization of each adapter, the data separation unit 4a and the data multiplexing unit 1
The switch 8a is controlled so that 1a is connected.

The switch 9a has almost the same function as the switch 8a, and is different only in that one of the switching targets is not the output of the B1 channel of the data separation unit 4a but the output terminal of the B2 channel. . The link pattern detection unit 10a detects the above-described link pattern from the data flowing on the B1 or B2 channel, and reports this to the Dch protocol control unit 6a together with the type of the detected B channel.

The data multiplexing unit 11a switches the switch 8 at the timing specified by the Dch protocol control unit 6a.
a, and the information output from the switch 9a is time-division multiplexed and sent to the dedicated line LC so as to conform to the protocol of the information channel on the dedicated line LC. The data separation unit 12a separates the information sent from the adapter 2b via the dedicated line LC into the B1 channel and the B2 channel at the timing specified by the Dch protocol control unit 6a, and outputs the separated information.

Next, the operation of the dedicated line ISDN terminal accommodating apparatus having the above configuration will be described. In the following, it is assumed that information (user data) is transmitted from the ISDN terminal 1a to the ISDN terminal 1b. First, when the ISDN terminal 1a makes a call using the D channel for connection with a communication partner, this information is transmitted to the adapter 2a via the cable 3a. The data separation unit 4a outputs this information to B1, B2,
D is separated into each channel. Then, the Dch protocol control unit 6a analyzes the control information placed on the D channel, recognizes the call, and checks whether there is an empty B channel using the management information in the Dch protocol control unit 6a.

If the B1 and B2 channels are currently transmitting data and there is no vacant B channel, the Dch protocol control unit 6a uses the D channel to send a rejection notification for the call using the D channel. The data is sent to the multiplexing unit 5a. Next, the data multiplexing unit 5a time-division multiplexes the information of each channel and sends out the information to the ISDN terminal 1a via the cable 3a. Thus, the ISDN terminal 1a can recognize that the communication has been rejected.

On the other hand, if there is an empty B channel, D
The channel protocol control unit 6a performs the following process. In the following, it is assumed that the B2 channel is selected as an empty B channel. First, the Dch protocol control unit 6
a controls the switch 9a to connect the link pattern generation unit 7a to the data multiplexing unit 11a. Concurrently, the Dch protocol control unit 6a instructs the link pattern generation unit 7a to generate a link pattern. Then, the generated link pattern is time-division multiplexed by the data multiplexing unit 11a via the switch 9a and sent to the adapter 2b through the dedicated line LC.

On the side of the adapter 2b, the data separation unit 12b
The B1 and B2 channels are separated and output. Then, the link pattern detection unit 10b detects the link pattern placed on the B2 channel, and
The Dch protocol controller 6b is notified together with the type of the detected B channel (that is, the B2 channel). The Dch protocol controller 6b controls the switch 9b corresponding to the B2 channel, connects the link pattern generator 7b and the data multiplexer 11b, and instructs the link pattern generator 7b to generate a link pattern. Thus, the link pattern is time-division multiplexed by the data multiplexing unit 11b through the switch 9b and sent to the adapter 2a via the dedicated line LC.

On the adapter 2a side, after the data from the adapter 2b is separated by the data separation unit 12a, the link pattern detection unit 10a detects the above-mentioned link pattern, and informs that the link pattern has been detected on the B2 channel. This is reported to the Dch protocol control unit 6a. As described above, the link pattern is detected on both adapter sides, and the link is established.

Then, the Dch protocol controller 6a
Controls the switch 9a to connect its output to the data multiplexing unit 11a. Similarly, the Dch protocol control unit 6
b also outputs its output via the switch 9b to the data multiplexing unit 1.
1b. Next, the Dch protocol controller 6a sends a call message to the switch 9a. This message is transmitted from the switch 9a → the data multiplexing unit 11a → the dedicated line L
The data is transmitted in the order of C, and is output from the output terminal on the B2 channel side of the data separation unit 12b.

On the other hand, the Dch protocol control unit 6b monitors the data flowing on the B2 channel of the data separation unit 12b.
When output from b, it is fetched internally, instructs the data multiplexing unit 5b to perform a multiplexing operation, and sends the fetched outgoing call message to the data multiplexing unit 5b as control information on the D channel. As a result, the message is time-division multiplexed by the data multiplexing unit 5b, and transmitted via the cable 3b.
The message is sent to the SDN terminal 1b, and as a result, an incoming call is made.
As described above, the link sequence between the adapter 2a and the adapter 2b is completed.

Next, user data is exchanged between ISDN terminals using the B2 channel. Therefore, Dc
h protocol control unit 6a controls switch 9a,
B2 channel output of data separation section 4a and data multiplexing section 1
1a is connected. Then, the user data transmitted from the ISDN terminal 1a is transferred from the cable 3a to the data separation unit 4a.
The data flows from the switch 9a, the data multiplexing unit 11a, the dedicated line LC, the data demultiplexing unit 12b, the data multiplexing unit 5b, and the cable 3b, and is sequentially transferred to the ISDN terminal 1b.

Thereafter, when the user data transmission processing is completed and the ISDN terminal 1a disconnects the link, the same processing as in the case of establishing a link is performed. That is, the link pattern is sent from the adapter 2a to the adapter 2b by using the B2 channel, and the link pattern is returned, and the link pattern is returned from the adapter 2b to the adapter 2a. Next, a link disconnection message is sent from the adapter 2a to the adapter 2b using the B2 channel, and when the message reaches the adapter 2b, the link disconnection process is completed.

The subsequent communication is performed in the same manner as described above. Here, when transmitting user data from the ISDN terminal 1b to the ISDN terminal 1a, a link pattern and various messages are transmitted in the opposite direction. When the B1 channel is selected instead of the B2 channel, the switches 8a and 8b
Are used to switch link patterns and message transmission.

In the above embodiment, 2B + D has been described for the sake of simplicity. However,
It is needless to say that the present embodiment can be applied to a communication interface such as 23B + D having 23 B channels by expanding the embodiment and limiting the number of information channels that can be connected according to the speed of the dedicated line.

[0034]

As described above, according to the present invention,
The control information from the ISDN terminal is reloaded on the information channel, time-division multiplexed with the user data and transmitted to the dedicated line, and the control information on the information channel transmitted via the dedicated line is reloaded on the control channel to transmit the information channel. Since the above user data is time-division multiplexed and sent to the ISDN terminal, the control channel and the information channel that require
The effect is obtained that the SDN terminal can be easily connected to a dedicated line such as a 128 kbps super digital used for communication through the information channel.

Since the ISDN terminal can be connected to the dedicated line, even if the terminal is switched from the ISDN to the dedicated line, the ISD
N terminal can be used as it is, and even if there is a plan to switch from dedicated line to ISDN in the future, only the ISDN terminal can be purchased and the dedicated line can be used until switching to ISDN. This has the advantage of eliminating the need for extra costs.

According to the second aspect of the present invention, the control information is transmitted by selecting an empty channel from a plurality of information channels, so that if any of the information channels is unused, the control is performed. Since channel communication is possible,
The effect is obtained that the idle time of the information channel is reduced and the line can be used more efficiently. Claim 3
According to the described invention, establishment of a link between ISDN terminals,
Since the disconnection control is realized by the return of the link pattern using the information channel, the effect is obtained that the user data and the information of the link control can be transmitted in a mixed state on the information channel.

[Brief description of the drawings]

FIG. 1 is an ISDN for a dedicated line according to an embodiment of the present invention.
It is a block diagram showing the structure of a terminal accommodation apparatus, and the connection form with the terminal etc. connected to the said apparatus.

FIG. 2 shows a dedicated line ISDN shown in FIG.
It is a block diagram showing the structure of another ISDN terminal accommodation device for exclusive use lines arrange | positioned facing a terminal accommodation device, and the connection form with the terminal etc. which were connected to the said device.

[Explanation of symbols]

1a, 1b: ISDN terminal, 2a, 2b: Adapter, 3
a, 3b: cable, 4a, 4b, 12a, 12b: data separation unit, 5a, 5b, 11a, 11b: data multiplexing unit, 6a, 6b: Dch protocol control unit, 7a, 7b
... Link pattern generator, 8a, 8b, 9a, 9b ... Switch, 10a, 10b ... Link pattern detector, LC
… Dedicated line

Claims (3)

[Claims] 1. An exclusive line ISD for accommodating an ISDN terminal that performs communication by time division multiplexing a control channel and an information channel in a dedicated line used for communication using the information channel.
N terminal accommodating apparatus, wherein first extraction means for extracting control information used for controlling the information channel from time-division multiplexed data transmitted from the ISDN terminal from the control channel, and the first extraction means First multiplexing means for time-division multiplexing the control information extracted by the control information and user data loaded on the information channel of the time-division multiplexed data on the information channel and transmitting the multiplexed data to the dedicated line; A second extracting means for extracting, from the information channel, the control information carried on the information channel of the line data among the line data transmitted from the destination terminal of the ISDN terminal via the dedicated line; Replacing the control information extracted by the second extracting means on the control channel, together with the user data of the line data on the information channel And a second multiplexing means for performing time-division multiplexing and transmitting the time-division multiplexed data to the ISDN terminal. 2. The apparatus according to claim 1, wherein the information channel includes a plurality of information channels, and a channel selection unit that selects an empty channel from the information channels. The first and second multiplexing means time-division multiplexes the control information and the user data using the information channel on the free channel side. Line ISDN terminal accommodation device. 3. A pattern generating means for generating a link pattern used for establishing or disconnecting a link between the ISDN terminal and the destination terminal; and the link sent from the pattern generating means on the destination terminal side. 2. A pattern detecting means for detecting a pattern, and a transfer means for transferring the link pattern to the information channel as a response to the link pattern sent from the destination terminal. Or the dedicated line ISDN terminal accommodating device according to 2.