JPH04288750A - Isdn terminal adapter - Google Patents

Abstract

PURPOSE:To economize a communication tariff by retuning a call originating request destination in a device when the destination is the own station. CONSTITUTION:A switch 5 for return is a switch for returning data from one of DTE interfaces 3 and 4 of A and B channels to the other interface. When a call is originated at the A channel and incoming to the B channel and there is a call originating request from the A channel, a CPU part 11 recognizes a caller number supplied from the first DTE interface 3 as the caller number of the B channel, controls the switch 5 for return and forms a loop so as to connect the first and second DTE interfaces 3 and 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal adapter for communicating via ISDN (Integrated Services Digital Network), and more particularly to an ISDN terminal adapter supporting two ports.

0002

2. Description of the Related Art A conventional ISDN terminal adapter will be described in detail with reference to FIG. Traditional ISDN
The terminal adapter is connected to a first data terminal equipment (DTE) 1 to which an A channel is assigned, a second data terminal equipment 2 to which a B channel is assigned, and an ISDN 10. A conventional ISDN terminal adapter has a first DTE interface 3 connected to a first data terminal device 1, a second DTE interface 4 connected to a second data terminal device 2, and a second DTE interface 4 connected to an ISDN 10. I interface section 9. 1st DT
A first speed matching section 6 is connected between the E interface 3 and the I interface section 9, and a second speed matching section 7 is connected between the second DTE interface 4 and the I interface section 9. ing. I interface section 9 is D
It is connected to the channel control section 8. The first DTE interface 3 electrically converts transmitted data from the first data terminal device 1 and received data to the first data terminal device 1 . The second DTE interface 4
The transmission data from the second data terminal device 2 and the reception data to the second data terminal device 2 are electrically converted. The first rate matching unit 6 converts the rate of the transmission data from the first DTE interface 3 and the rate of the reception data to the first DTE interface 3. The second speed matching section 7
converting the rate of the transmitted data from the second DTE interface 4 and the received data to the second DTE interface 4. D channel control unit 8 performs call control. The I interface section 9 connects the first and second speed matching sections 6 and 7 with D.
The transmission data and reception data of the channel control unit 8 are time-division multiplexed. D channel control unit 8, first and second DTE
The interfaces 3 and 4 are controlled by the CPU section 11.

Data communication using a conventional ISDN terminal adapter is performed as follows. That is,
Upon receiving a call request from the DTE, the D channel control unit 8 performs call processing via the ISDN 10. On the other hand, when a call is received, the D channel control unit 8 processes the call via the ISDN 10.

0004

[Problems to be Solved by the Invention] As described above, in the conventional ISDN terminal adapter described above, one DTE
When you make a call request from , the call destination is the other D
If it is TE, the call is looped back to the own ISDN terminal adapter via the ISDN 10 and the exchange. In this case, since the ISDN terminal adapter accesses the exchange, a communication fee equal to that of a subscriber phone is charged.

[0005] An object of the present invention is to provide an ISDN terminal adapter that can return calls within the device to save communication charges when the call request destination is the local station.

[0006]

[Means for Solving the Problems] An ISDN terminal adapter according to the present invention is a terminal adapter that performs communication via ISDN, and electrically transmits data transmitted from a data terminal device and received data to the data terminal device. A DTE interface for two channels to be converted, a speed matching part for two channels to convert the speeds of the transmission data and the reception data, a switch part for returning data from one of the DTE interfaces to the other, and a switch part for performing call control. a D channel control unit for one channel, an I interface unit that time-division multiplexes the transmission data and reception data of the rate matching unit and the D channel control unit, the switch unit, and the D channel control unit. CPU
It is characterized by having a part.

[0007]

[Operation] When a call request is made from one data terminal device, the CPU section determines whether or not the destination of the call request is the other data terminal device of the own station. If so, C
The PU unit controls the switch unit to form a loop so that the DTE interfaces are connected to each other. That is,
Folds back inside the device.

[0008]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an ISDN terminal adapter according to one embodiment of the present invention. The ISDN terminal adapter according to this embodiment has the same configuration as a conventional ISDN terminal adapter, except that it includes a return switch 5. Therefore, the same reference numerals are given to the same components as in the conventional one, and the explanation thereof will be omitted.

[0009] The operation when a call is originated on the A channel and received on the B channel will be described below. The CPU section 11 stores in advance the caller number of the A channel and the caller number of the B channel. The first channel to which A channel is assigned
The data terminal device 1 issues a call request using a command. At this time, the caller number is supplied to the CPU section 11 via the first DTE interface 3. When there is a call request from channel A, the CPU section 11 uses the caller number supplied from the first DTE interface 3 and the stored A channel.
Compare the caller number of the channel and the caller number of the B channel. In this example, the CPU unit 11 recognizes the caller number of the B channel. Therefore, the CPU section 11
The return switch 5 is controlled to form a loop so that the first DTE interface 3 and the second DTE interface 4 are connected. The CPU section 11 does not access the D channel control section 8. The operation when a call is originated on the B channel and received on the A channel is also similar to the operation explained above.

0010

[Effects of the Invention] As explained above, according to the present invention, a return switch is added to the front stage of the speed matching section of each channel. Since it is folded back inside the adapter, it has the effect of saving communication charges.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating an ISDN terminal adapter according to one embodiment of the invention.

FIG. 2 is a block diagram illustrating a conventional ISDN terminal adapter.

[Explanation of symbols]

1 A channel data terminal device 2 B channel data terminal device 3 A channel DTE interface 4 B channel DTE interface 5 Return switch 6 A channel speed matching section 7 B channel speed matching section 8 D channel control section 9 I interface section 10 ISDN 11 CPU section

Claims (3)

[Claims] 1. A terminal adapter that communicates via ISDN, comprising: a DTE interface for two channels that electrically converts data transmitted from a data terminal device and data received by the data terminal device; a speed matching unit for two channels that converts the speed of the received data; a switch unit that loops back data from one of the DTE interfaces to the other; a D channel control unit for one channel that performs call control; An ISDN terminal adapter comprising: an I interface section that time-division multiplexes transmission data and reception data of the D channel control section and the D channel control section; and a CPU section that controls the switch section and the D channel control section. 2. The CPU unit includes a storage unit that stores in advance a caller number of the data terminal device, and a caller number supplied from the DTE interface when a call is requested and the stored caller number. and a comparison means for comparing the DTE interfaces by controlling the switch unit to connect the DTE interfaces when the comparison means detects a match between the supplied caller number and the stored caller number. 2. An ISDN terminal adapter according to claim 1, further comprising means for forming a loop such that the ISDN terminal adapter is connected to the ISDN terminal adapter. Claim 3: A first channel to which a first channel is assigned.
A terminal adapter is connected to a second data terminal device to which a second channel is assigned, and performs communication via ISDN, the terminal adapter transmitting data from the first data terminal device and the second data terminal device to which a second channel is assigned. a first DTE that electrically converts received data to a first data terminal device;
a second DTE interface that electrically converts transmission data from the second data terminal device and reception data to the second data terminal device; a second DTE interface that electrically converts transmission data from the first DTE interface; a first rate matching unit that converts the rate of received data to the first DTE interface; and a first rate matching unit that converts the rate of transmitted data from the second DTE interface and received data to the second DTE interface. 2, a D channel control unit that performs call control, and the IS
In the ISDN terminal adapter, the ISDN terminal adapter has an I interface unit connected to a DN and time-division multiplexing the transmission data and reception data of the first and second rate matching units and the D channel control unit. determining means for determining whether or not the destination of the call request from one of the second data terminal devices is the other of the first and second data terminal devices; An ISDN terminal adapter comprising switch means for connecting the first DTE interface and the second DTE interface.