JP2000244485A - Terminal adaptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a terminal adaptor TA during the communication. SOLUTION: A control processing section 205 of a host device 200 sets control data and identification information of a TA 100 to an IP datagram whose destination is an IP address assigned to a TCP/IP processing section 203 and the TA 10 and transmits the datagram to the TA 100 via a point-to-point protocol PPP processing section 202. A branch processing section 104 of the TA 100 extracts a PPP packet including the IP datagram to which the identification information is set among PPP packets sent to the TA 100 and gives the set IP datagram to a TCP/IP processing section 105. The TCP/IP processing section 105 transmits control data set in the extracted IP datagram to a TA control processing section. An information data processing section 103 transmits other PPP packets than that including the IP datagram extracted by the branch processing section 104 to a line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-ISDN
The present invention relates to a terminal adapter used for connecting to a terminal adapter.

[0002]

2. Description of the Related Art A TA (Terminal Adapter) is a device for connecting a non-ISDN terminal such as an analog telephone, an analog facsimile or a personal computer to the ISDN. The TA has a basic interface corresponding to a 2B + D channel. Things are widespread.

[0003] The two B
It is possible to provide circuit switching connection service for two lines using channels, and non-ISDN terminals can use TA to
One or two lines on ISDN can be used.

[0004] As a protocol for establishing a data link using a serial line between two points, RFC is used.
PPP: Point to Point Protocol specified in 1661
And MP specified in RFC 1990: The PPP Multilink P
rotocol is known. MP is an extension of PPP, in which PPP establishes a data link with one link set on one serial line, whereas MP sets multiple data sets, one for each serial line. By establishing a data link using the link of the above, a high-speed data link is realized as compared with PPP which uses a plurality of serial lines at the same time. In some cases.

That is, the TA is provided with a PPP-MP conversion function, and as shown in FIG. 7, the TA establishes a PPP data link between a host device (such as a personal computer) connected to the extension port of the TA and a partner device. When establishment is requested, the TA establishes two lines using two B channels with the partner device, and sets up a link on each line to set up an MP data link using the two links. To establish. Then, the TA performs the conversion of the data link of the MP with the counterpart device and the data link of the PPP with the host device, so that the host device that does not support the MP but only supports the PPP, Provide high-speed data link by MP.

[0006]

In the above-described embodiment, the TA
When MP is used by using the PPP-MP conversion function, two B channels on the basic interface are occupied by communication of one host device connected to the extension port of the TA. Therefore, other devices connected directly to the basic interface or via the TA cannot use the line during this time.

On the other hand, directly or
When a new call setting request is generated by a call from another device connected via the TA or a call from ISDN, the number of lines used for communication with the host device is reduced from two lines to one line, As a result, there is a case where it is desired to allocate an empty line to a call corresponding to the setting request.

Here, according to the study of the present inventors, as a method for realizing such a function, the TA autonomously
A first method of reducing the number of lines used for communication of a device connected to a TA from two lines to one line when a new call setting request occurs, and a method of newly generating a call from a device connected to a TA. When a setting request is issued, the number of lines used for communication of the device connected to the TA is controlled from two lines to one line.
There are two approaches.

Here, regarding the first method, the UNI of ISDN
At point T where (user / network interface) is formed,
Multiple TA and ISDN terminals can be connected. If the device that newly calls is not a device connected to the extension port of the TA using the two lines, the TA using the two lines cannot detect the call of another device. Problems arise. Also, since incoming calls from ISDN using two lines can only be answered by TAs using two lines, even if the number of lines used by a TA using two lines is reduced, the extension port of this TA Equipment other than the equipment connected to
A problem arises in that the incoming call cannot be connected.

Accordingly, the present invention reduces the number of lines used for communication of a device connected to a TA from two lines to one line when a new call setting request occurs, and allows another device connected to a point T to change the line. The operation that can be used can be performed autonomously
The task is to provide TA.

Regarding the second method, according to Hayes-AT, which is widely used as a TA control procedure, when controlling a TA during communication, the TA is temporarily set to an escape mode.
It is necessary to restart communication after suspending communication by controlling the TA and controlling the TA, and another widely used TA control procedure, ITU-T, V.25bis, controls the TA during communication. Can not do it. For this reason, depending on these, it is not possible to control the number of lines used for communication of the device connected to the TA from two lines to one line without interrupting the communication of the device connected to the TA.

Accordingly, an object of the present invention is to make it possible to control a TA without interrupting communication of a device connected to the TA.

[0013]

In order to achieve the above object,
The present invention is, for example, a terminal adapter connected to a host device via a serial interface and providing the host device with a communication function via ISDN.
When communication is performed via the serial interface, a specific IP address set in advance among IP datagrams transmitted from the host device via the serial interface is set as a destination.
Extract IP datagrams and ISDN the remaining IP datagrams
And a control unit for controlling the operation of the terminal adapter based on the data stored in the extracted IP datagram.

According to such a terminal adapter,
Sends control data to the terminal adapter using IP datagrams during communication. Since the IP datagram can coexist with the IP datagram used by the host device for communication with another device, the terminal adapter can be controlled even during communication.

Further, in order to achieve the above object, the present invention provides, for example, a host device connected to an ISDN user network interface, and provides the host device with a communication function via a B channel on the user network interface. A terminal adapter that connects a plurality of calls each using one B channel and provides a communication function through a plurality of B channels connected to the host device, from ISDN,
Detecting means for detecting that a release completion message including a reason indication indicating that there is no free channel has been transmitted on the user-network interface; and detecting means for connecting when the detection means detects the release completion message. B at least one of the existing calls is disconnected and used by that call B
Control means for releasing the channel.

Here, the release completion message including the reason indication indicating that there is no free channel is issued from ISDN when there is no free B channel when another device requests a call setup by a call setup message. Therefore, according to such a terminal adapter, when a new call setting request is issued, the number of lines used for communication of the device connected to the TA is reduced from two lines to one line, and the other device connected to the T point can be used. The operation of making the line available can be performed autonomously.

Further, the present invention provides a method for achieving the above object,
A terminal adapter which is connected to a host device and an ISDN user / network interface and provides the host device with a communication function via a B channel on the user / network interface, wherein a plurality of calls each using one B channel are provided. When a call setting message indicating a communication incoming call notification is received from ISDN during a period in which the communication function is provided through a plurality of B channels connected to the host device, the connected call is connected. Means for disconnecting at least one of the calls and releasing the B channel used by the call, and after releasing the B channel, the call setup message transmits a response message responding to the call requesting the setup to ISDN, A terminal comprising: means for transmitting an interruption message for interrupting the call to the ISDN; and means for presenting, when the call is interrupted, a notice to that effect. To provide the adapter.

Here, when a new call is requested from the ISDN side, the call setup message including the channel absence as a channel identifier is transmitted when there is no free B channel.
According to such a terminal adapter, when a new call setting request is issued, the number of lines used for communication of the device connected to the TA is reduced from two lines to one line, and the interrupted call is reduced. By restarting from another device, the other device connected to the point T can use the line.

[0019]

Embodiments of the present invention will be described below.

First, a first embodiment will be described.

In the first embodiment, the TA can be controlled without interrupting the communication of the device connected to the TA.

FIG. 1 shows a configuration of a terminal apparatus (TE) according to the present embodiment.

As shown, the terminal device comprises a host device 200 which is an electronic computer and a TA 100. TA
100 is UN in the line interface control unit 101
Connect to the T point that provides the basic interface as I and RS
Interface control unit 1 according to -232C etc.
At 07, it is connected to the host device 200. Also,
The host device 200 is connected to the TA 100 in the serial interface control unit 201 according to RS-232C or the like.

The host device 200 includes a PPP processing unit 202 for processing PPP, a TCP / IP processing unit 203 for processing TCP / IP,
P / IP use application group 206, control processing unit 20
5. Issue AT command in accordance with Hayes-AT to TA100, and
The terminal processing unit 204 receives a result code from the terminal 100. However, these represent functional units realized on the host device by executing the program. Now, the PPP processing unit 202 transmits the PPP data link using the line provided by the TA 100 to the TCP / IP processing unit 2.
The TCP / IP processing unit 203 provides a TCP connection using an IP packet transmitted / received on the PPP data link to the TCP / IP.
/ IP use application group 206 and control processing unit 203
To provide. The control processing unit 203 and the TCP / IP application group 206 send and receive data over a TCP connection. Here, the TCP / IP processing unit 203 is
3. An IP datagram storing a TCP segment in which data transmitted / received by the TCP / IP application group 206 is stored in a TCP data field is transmitted / received to / from the PPP processing unit 202.
The PP processing unit 202 transmits and receives the PPP packet storing the IP datagram transmitted and received by the TCP / IP processing unit 203 to and from the TA 100 via the serial interface control unit 201. The IP datagram includes an IP address indicating the transmission destination as a destination address.

Next, the TA 100 includes an information data processing section 103 for processing data transmitted and received on the B channel line,
A branch processing unit 104 that performs conversion between a P packet and an IP datagram, a TCP / IP processing unit 105 that performs the same TCP / IP processing as the TCP / IP processing unit 203 of the host device 200, and a TCP / IP processing unit 105 It has a TA control processing unit 106 for transmitting and receiving data on a provided TCP connection, and a line control unit 102 for performing line control.

The operation of such a terminal device will be described below.

First, the initial setting operation of the TA 100 will be described.

In the initial setting operation, the terminal processing unit 204 sends an AT command requesting the setting of a specific IP address and specific identification information via the serial interface control unit 201 according to a user instruction or a predetermined initial setting file. Issue to TA100. In the TA 100 that is not communicating in this state, the AT command is sent to the TA control processing unit 106 via the serial interface control unit 107. The TA control processing unit 106
According to the AT command, the IP address and the identification information are set internally, and the IP address is set in the TCP / IP processing unit 105, and an appropriate result code indicating the completion of the setting is set via the serial interface control unit 107. Send to host device 200. In the host device 200, the result code is sent to the terminal processing unit 204 via the serial interface 202, and is sent to the terminal processing unit 204.

Next, the TCP / IP application group 20
TA100 when 6 is performing communication using a line
Will be described.

The control processing unit 203 of the host device 200
When the control of the TA 100 is desired, the destination port number of the TCP segment is set to the port number previously assigned to the TA control processing unit 106 of the TA 100, and the source port number is set to the control processing unit 2.
03, the port number assigned in advance to the IP address, and the destination address of the IP datagram set to the TA 100 in the initial setting.
After setting the TCP / IP processing unit 202 so that the source address is the IP address assigned to the host device 200, the data including the identification information set in the TA 100 in the initial setting is transmitted to the TCP / IP processing unit 202. send.

A PPP packet storing an IP datagram storing a TCP segment storing the data is a TCP / I packet.
The packet is sent to the TA 100 together with the PPP packet storing the IP datagram storing the TCP segment storing the data transmitted by the P utilization program.

On the other hand, during communication in the TA 100, the PPP packet sent from the host device 200 is temporarily held in the information data processing unit 103. Branch processing unit 104
Indicates whether the destination address of the IP datagram included in the copy of the stored PPP packet matches the IP address set in the initial setting, and whether the destination address of the IP datagram is in the TCP data field in the TCP segment included in the IP datagram. It is checked whether or not the data set includes the identification information set in the initial setting. If the IP addresses match and the identification information is included, the IP datagram is sent to the TCP / IP processing unit 105 and Then, the information data processing unit 103 is instructed to discard the PPP packet storing the IP datagram.

On the other hand, the information data processing unit 103 discards a PPP packet instructed to be discarded among the PPP packets received from the host device 200, and does not transmit it to the line on the B channel. On the other hand, other packets are transmitted to the line on the B channel via the line interface control unit 101. The information data processing unit 103
Stores the IP datagram received from the TCP / IP processing unit 105 in a PPP packet and sends it to the host device 200 via the line interface control unit 101 together with the PPP packet received from the line on the B channel. However, TCP / IP
Stores IP datagram received from processing unit 105
The PPP packet is created and transmitted so as not to affect the PPP data link between the PPP processing unit 202 of the host device 200 and the partner device.

By the operations of the branch processing unit 104 and the information data processing unit 103, the PPP processing unit 202 of the host device 200 is placed between the TCP / IP processing unit 203 of the host device 200 and the TCP / IP processing unit 103 of the TA 100. Means that a data link using a part of the PPP data link to be processed is set.

By the above operation, the host device 20
The IP datagram storing the data of the control processing unit 203 of 0 is sent to the TCP / IP processing unit 105. TCP / IP processing unit 1
05 restores a TCP segment from the received IP datagram and sets a TCP connection on a data link with the TCP / IP processing unit 203 of the host device 200. However, what flows on this TCP connection is the TA control processing unit 10 as the destination port number stored in the IP datagram having the IP address initialized as the destination address.
Of the TCP segments having the port number assigned to the control processing unit 203 as the source port number, the port number of No. 6 is limited to only the TCP segment storing the identification information initially set in the data of the TCP data field.

Now, the TCP / IP processing unit 105 transmits the set TC
The data in the TCP data field of the TCP segment received on the P connection is passed to the TA control processing unit 106. The TA control processing unit 106 receives the received data as control information and performs control according to the content.

When transmitting the control result to the control processing unit 203 of the host device 200, the TA control processing unit 106 passes data indicating the control result to the TCP / IP processing unit 105. TC
The P / IP processing unit 105 passes the IP datagram storing the TCP segment storing the data to the branch processing unit 104, and thereby the TCP / IP processing unit 20 of the host device 200.
3 on the data link between them. However, at this time, the TCP / IP processing unit 105 sets the destination port number and the source port number of the TCP segment as
Received on data link with TCP / IP processing unit 203
The source port number and the destination port number of the TCP segment are set, and as the destination address and the source address of the IP datagram, the IP datagram of the IP datagram received on the data link between the host device 200 and the TCP / IP processing unit 203 is set. The source address and the destination address are used.

From the TCPP / IP processing unit 105 to the host device 20
The IP datagram transmitted on the data link to the TCP / IP processing unit 203 of the host device 200 is received by the TCP / IP processing unit 203 of the host device 200, and the received TCP / IP processing unit 203 receives the IP datagram. And restores a TCP segment, and sets a TCP connection on a data link between the TA 100 and the TCP / IP processing unit 203 of the device 200 of the TA 100. Then, the data in the TCP data field of the TCP segment received on the set TCP connection is transferred to the control processing unit 205. The control processing unit 205 obtains the result of the control performed from the received data.

The terminal device according to the present embodiment has been described above.

As described above, according to the present embodiment, even during communication, communication from the host device can be performed without interrupting communication.
TA can be controlled. In addition, since the control processing unit 205 of the host device 200 can be realized as an application program using standardized TCP / IP, the control processing unit 205 can be easily performed without affecting the OS of the host device 200 or the like. Can be created.

In this embodiment, the host device 200
From the control processing unit 205 to the TA control processing unit 106 of the TA 100
Control information to be sent to not only the IP address but also the identification information, as shown in FIG.
Even if another device having the same IP address as the IP address initially set in the TA control processor 106 of the device 100 exists on the network to which the host device 200 is connected, data addressed to this other device is not The TA control processing unit 10
6 can be sent to the TA control processing unit 106, and does not hinder communication between the host device and other devices.

Note that if it is possible to guarantee that the IP address initially set in the TA control processing unit 106 of the TA 100 does not overlap with another device, the processing relating to the identification information in the above embodiment may be unnecessary. For example, if there is a private address (RFC1918) that is guaranteed not to be used on the network to which the host device is directly connected, the private address is assigned to the TA control processing unit 106, and the processing related to the identification information is unnecessary. Can be.

Hereinafter, a second embodiment of the present invention will be described.

In the second embodiment, when a TA autonomously makes a new call setting request, the number of lines used for communication of a device connected to the TA is reduced from two to one, and the number of lines is reduced. It is to be made available to other devices.

FIG. 3 shows user-side equipment to which the TA according to the present embodiment is applied.

As shown, the user-side equipment has a form in which a plurality of TAs or ISDN terminals (TEs) are bus-connected to a T point where a UNI providing a basic interface is formed.

Now, reference numeral 300 in FIG.
TA.

Hereinafter, the TA 300 will be described.

FIG. 4 shows the configuration of the TA 300.

In the figure, reference numeral 305 denotes a serial interface control unit for processing communication with the host device 400 connected to the extension port; 306, a circuit switching control unit for processing call control using a D channel with ISDN; Is a B1 channel control unit for controlling data transfer using the B1 channel, 3
08 is a B2 channel control unit for controlling data transfer using the B2 channel, 310 is a monitor for controlling each unit, 311
Is a display device.

Hereinafter, the operation of the TA 300 will be described.

Now, the TA 300 is connected to the two B channels used by the host device 400 connected to the extension port.
It is assumed that two lines are connected.

At this time, the circuit switching control unit 30 of the TA 300
6 is layer 3 transmitted from ISDN to D channel on T point
Monitor messages. Then, as shown in FIG.
If the DN detects a release completion message for the other device that includes no channel in the cause indication, it indicates that the other device has originated the call, and disconnects one of the connected B channels. It transmits to ISDN, receives release from ISDN, disconnects by a disconnection sequence of transmitting release complete message to ISDN, transmits this to host device 400, and displays that there is free B channel in display device 31.
1 is displayed.

Thereafter, the user who sees this display can use the line on the vacant B channel by calling again from another device.

Further, the TA 300 is provided on the two B channels used by the host device 400 connected to the extension port.
As shown in FIG. 6, when a call setup message with no channel identifier and a channel identifier is received from the ISDN by the incoming call notification function when the two lines are connected, as shown in FIG. Is sent to the ISDN, and the display device 311 displays that there is an incoming call during communication. And B connected
One of the channels is cut by the same cutting sequence as before, and this is transmitted to the host device 400. However,
This disconnection may be performed according to a user operation.

Then, a response message for the call of the call number that sent the call message is transmitted to ISDN,
If a response acknowledgment message is received from the
And receive an interrupt confirmation message from ISDN. When the interruption confirmation message is received, the processing for this call is terminated.

In this state, the call having this call number is in a suspended state, and the call is taken over by the device that has transmitted the resume message. When a suspend message that does not include the call identification is used, only one call can be suspended at the same time, and there is no need to specify a call to be resumed in the resume message, and a new call number can be used as the call number.

Therefore, the user who has recognized from the display of the TA 300 that there is an interrupted call transmits a resume message from another device. Thereafter, if the other device receives a restart confirmation message from the ISDN, the restart sequence is completed, the vacant B channel is allocated to the call that arrived earlier during communication, and the other device initiates the call. A line is connected to the calling apparatus, and communication can be performed between the two apparatuses.

The second embodiment of the present invention has been described above.

[0060]

As described above, according to the present invention, when a new call setting request is issued, the number of lines used for communication of the device connected to the TA is reduced from two lines to one line, and It is possible to provide a TA that can autonomously perform an operation of enabling a connected other device to use a line. Further, according to the present invention, the TA can be controlled without interrupting the communication of the device connected to the TA.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a terminal device according to a first embodiment of the present invention.

FIG. 2 shows a terminal device according to the first embodiment of the present invention.
FIG. 4 is a sequence diagram showing how TA control is performed.

FIG. 3 is a diagram illustrating user-side equipment to which a TA according to a second embodiment of the present invention is applied;

FIG. 4 is a block diagram illustrating a configuration of a TA according to a second embodiment of the present invention.

FIG. 5 is a sequence diagram showing an operation of a TA according to the second embodiment of the present invention.

FIG. 6 is a sequence diagram showing an operation of a TA according to the second embodiment of the present invention.

FIG. 7 is a diagram showing a conventional mode of using MP via TA.

[Explanation of symbols]

100 TA, 102 line control unit, 103, information data processing unit, 104 branch processing unit, 105 TCP / IP processing unit,
106 TA control processing unit, 107 serial interface, 200 host device, 201 serial interface, 204 terminal processing unit, 205 control processing unit, 206 TCP / IP application group, 300
TA, 305 Serial interface control unit, 306
Circuit switching control unit, 307 B1 channel control unit, 308
B2 channel control unit, 310 monitor, 311 display device, 400 host device

Claims (7)

[Claims] 1. A terminal adapter connected to a host device via a serial interface and providing the host device with a communication function via ISDN, wherein the serial interface is provided when the host device is performing communication via ISDN. Branching means for extracting an IP datagram destined for a predetermined specific IP address from among IP datagrams transmitted from the host device via the host device, and transmitting the remaining IP datagrams to the ISDN; Control means for controlling the operation of the terminal adapter based on the data stored in the datagram. 2. A terminal adapter connected to a host device via a serial interface and providing the host device with a communication function via ISDN, wherein the serial interface is connected when the host device is performing communication via ISDN. Among the IP datagrams sent from the host device via the host device, an IP datagram having a specific IP address set in advance as a destination and storing a specific identification value set in advance is extracted, and the remaining IP datagrams are subjected to IS.
A terminal adapter comprising: a branching unit for transmitting to a DN; and a control unit for controlling an operation of the terminal adapter based on data stored in an extracted IP datagram. 3. The terminal adapter according to claim 1, wherein said control means stores data obtained as a result of controlling operation of the terminal adapter when the host device is performing communication via ISDN. And transmitting the received IP datagram to the host device via the serial interface together with the IP datagram received from ISDN. . 4. The terminal adapter according to claim 1, wherein the host device does not perform communication via ISDN according to a predetermined command sent from the host device via the serial interface. And a means for setting the specific IP address. 5. A terminal adapter which is connected to a host device and an ISDN user / network interface and provides the host device with a communication function via a B channel on the user / network interface. During a period in which a plurality of calls to be used are connected and a communication function via a plurality of B channels connected to the host device is provided, a release completion message including a cause indicating that there is no available channel is transmitted from the ISDN to the user. Detection means for detecting transmission on the network interface, and when the detection means detects the release completion message, disconnects at least one of the connected calls and uses the call. And a control unit for releasing the B channel. 6. A terminal adapter which is connected to a host device and an ISDN user / network interface and provides the host device with a communication function via a B channel on the user / network interface. When a plurality of calls to be used are connected, and a communication function via a plurality of B channels connected to the host device is provided, when a call setting message indicating an incoming call notification is received from ISDN, the connection is established. Means for disconnecting at least one of the active calls and releasing the B channel used by the call; and after releasing the B channel, the call setup message sends a response message to the ISDN in response to the call requesting the setup to the ISDN. Means for transmitting to the ISDN a transmission message for transmitting and further interrupting the call. 7. The terminal adapter according to claim 6, further comprising means for presenting, when said call is interrupted, a notice to that effect.