JPH04199961A - Communication terminal equipment - Google Patents

Abstract

PURPOSE:To satisfy return loss specifications different in respective countries with one piece of hardware by providing a return loss specification corresponding part having a means which switches a transmission/reception level correction means correcting the change of an attenuation amount accompanied by means of the switching of a terminal resistance in correspondence with the group of the return loss specifications. CONSTITUTION:The transmission/reception level correction means which switches the terminal resistance and corrects the change of the attenuation amount accompanied by the switching of the terminal resistance is provided in the return loss specification corresponding part 6 provided on the secondary side of a transformer connecting lines L1 and L2 and MODEM 7 in an electrically insulated form. Then, the above means is suitably switched in correspondence with the groups A and B of the return loss specifications. Namely, a system control part 8 judges to which of the groups between the group A or the group B the specification of the country belongs. When it belongs to the group A, a relay 10 is switched to r1, a relay 11 to r3 and a relay to r5. When it belongs to the group B, the relay 10 is switched to r2, the relay 11 to r4 and the relay 12 to r6. Thus, the return loss specifications different in respective countries can be satisfied with one piece of hardware.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to communication terminal equipment, and in particular, standards regarding communication line terminals that differ depending on the country (so-called "PTT standard").
In particular, the present invention relates to a communication terminal device that satisfies standards regarding return loss with one piece of hardware.

[Prior Art] Since the standards regarding return loss in the PTT standard differ in different countries around the world, it has been practically impossible to satisfy this standard with one piece of hardware.

For this reason, traditionally, countries were divided into groups based on standards.
The circuit was changed for each group.

To deal with this, it may be possible to create a circuit that can handle a plurality of groups and switch between groups. An example of a conventional device of this type is the device disclosed in Japanese Patent Laid-Open No. 2-58957.

This device has means for switching the terminal impedance of the line to low impedance during communication operation and to high impedance while waiting for communication.

[Problem to be solved by the invention]

In the former of the above-mentioned conventional techniques, since it is necessary to change the circuit for each group, an increase in cost is unavoidable, and it is also troublesome from the viewpoint of product management.

Further, the latter of the above-mentioned conventional techniques switches impedance, and as described above, cannot be used to comply with the return loss standard in the PTT standard.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to solve the above-mentioned problems in the conventional technology, and to implement the return loss standards of the PTT standards, which differ in various countries around the world, with a single piece of hardware. An object of the present invention is to provide a communication terminal device that satisfies the requirements.

[Means for Solving the Problems] The above object of the present invention is to switch a terminating resistor on the secondary side of a transformer that couples a line and a modem in an electrically insulated manner, and furthermore, to A communication terminal device characterized in that it is provided with a return loss standard compatible unit having a transmitting/receiving level correcting means for correcting a change in attenuation amount, and a means for appropriately switching these levels in correspondence with a group of return loss standards, or On the secondary side of the transformer,
A return loss standard having a plurality of circuits each having the same impedance and having capacitors each having a capacity corresponding to a group of the return loss standard, and a means for appropriately switching these circuits to correspond to the group of the return loss standard. This is achieved by a communication terminal device characterized by being provided with a corresponding section.

[Function] In the communication terminal device according to the present invention, the first communication terminal device has a termination point in the return loss standard compatible part provided on the secondary side of the transformer that connects the line and the modem in an electrically insulated manner. In addition to switching the resistance, a transmitting/receiving level correcting means for correcting the change in attenuation due to switching of the terminating resistor is provided, and these are appropriately switched in correspondence with each of the above-mentioned groups. In the terminal device, a plurality of circuits are provided in the return loss standard compatible section so that impedances are equal to each other, and capacitors having capacitances corresponding to the respective groups are arranged,
Although there is a difference in the configuration in that these are made to correspond to each of the aforementioned groups and can be switched as appropriate, in both cases, a single piece of hardware is made to correspond to the return loss standards among the PTT standards that differ in each country. It is possible to realize a communication terminal device.

(2) [Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing an overview of a general system configuration of a facsimile machine, which is an example of a communication terminal device. In the figure, 1 is an off-hook detection unit that detects polarity reversal of the line LL and L2, and 2 is a TI.

The external equipment connected to T2 is an OH relay that switches between the telephone side and the facsimile modem side, 3 is a dial pulse sending unit that sends dial pulses and closes the DC circuit, 4
5 is a ringing detection unit that detects the ringing signal sent from the exchange, converts it into a binary value, and notifies it to the system control unit 8 of the facsimile; 5 connects the lines Ll and L2 to the facsimile side such as the modem 7 while electrically insulating them; Trance, 6
7 is a 2-wire/4-wire converter that separates the bidirectional signal from the line side into a transmitting signal and a receiving signal, 7 is a modem that modulates and demodulates the signal, and 8 is a system that controls the entire facsimile machine. The control section is shown. First according to the present invention
The facsimile machine is a 2-wire 4 in the system configuration described above.
The above-mentioned object is achieved by providing the line converter 6 with a special configuration. This will be explained in more detail below.

FIG. 2 is a diagram showing an example of the configuration of the two-line and four-line converter 6 in FIG. 1. The transformer 5 has a DC resistance on both the negative side and the secondary side, and the DC resistance on the secondary side is terminated with a resistor r for matching.

As mentioned above, in the past, countries were divided into groups according to standards, and the circuit was changed for each group.
, C2 were selected to have appropriate values. The portion surrounded by the broken line in FIG. 2 is a characteristic component of the 2-line and 4-line converter 6 of this embodiment.

FIG. 3 shows a more detailed configuration example of the portion surrounded by the broken line in FIG. 2. In this configuration example, the terminating resistor r in FIG. In addition to selecting one of .

Figure 4 (a) shows a detailed configuration example of the shaded areas A and B in Figure 3.
) and (b). Resistance rIT rl in Figure 3
, the resistances r, , r in Fig. 4(a), and the same (b
) are synchronously switched.

The circuit shown in FIGS. 4(a) and (b) has a terminating resistor r
, 'II rl is selected to compensate for the change in gain corresponding to the change in the termination condition. This makes it possible to keep the transmission level and reception level constant.

FIG. 5 shows an operation flowchart of the communication terminal device according to this embodiment. Here, the return loss standard is group A (reference is 600Ω system).

Belgium, etc.) and Group B (reference is network-based Nissui, etc.).

To explain the operation, first, when the country code is set to comply with the standard (step 21), the aforementioned system control unit 8
determines whether the country belongs to group A or group B (step 22), and if it is group A, then in step 23, relay lO is set to r, relay 11 is set to r, Switch the relays 12 to r, respectively. Also, if it is group B, step 24
In, relay 10 is set to r8, relay 11 is set to r,
Switch the relays 12 to r, respectively. Thereby, the communication terminal device can be set to substantially comply with each return loss standard.

According to the above embodiment, the r
By selecting values from 1 to r and switching these appropriately, it is possible to substantially comply with the return loss standards of each country around the world with a low-cost device, and to respond to changes in transmitting and receiving levels. Effects can be obtained.

FIG. 6 is a diagram showing an outline of the system configuration of a facsimile machine showing another embodiment of the present invention.

In the figure, symbols 1 to 4 indicate the same components as shown in FIG. 1, and 5A is line Ll.

A transformer electrically insulates and couples L2 and the facsimile side, 8A is a system control unit that controls the entire facsimile machine, and 9 is a return loss standard compliance unit to be described later.6 The facsimile machine according to this embodiment is By having the above-mentioned return loss handling section 9, the above-mentioned object is achieved. This will be explained in detail below.

FIG. 7 is a diagram showing a configuration example of the transformer 5A and return loss handling section 9 in FIG. 6. The secondary side of the transformer 5A is wound so that the impedances of the 6th to 10th bins and the 8th to 1Oth bins are equal. As a result, by selecting an appropriate value for the set of capacitors (C1°C2) and (C3, C4), it is possible to comply with return loss standards that vary from country to country.

As mentioned above, in the past, countries were divided into groups according to standards, and the circuit was changed for each group.
In this system, only one set was provided, and one with an appropriate value was selected.

In this embodiment, as in the case of the previous embodiment, the return loss standard is divided into A group with a reference of 600Ω and B group with a network system, and capacitors (C1, C1, C2) and (
An appropriate value is selected for the pair C3, C4).

FIG. 8 shows an operation flowchart of the communication terminal device according to this embodiment. To explain the operation based on Fig. 8,
First, when a country code is set in order to comply with the standard (step 31), the system control unit 8A described above determines whether the country belongs to the above-mentioned group A or group B (step 32). If so, in step 33 the relay 13 is switched to allbl.

If it is group B, then in step 34 the relays 13 are switched to aR and b, respectively. Thereby, the communication terminal device can be set to substantially comply with each return loss standard.

According to the above embodiment, the appropriate 0
By selecting values of 1 to C4 and switching these appropriately, it is possible to substantially comply with the return loss standards of each country around the world with a low-cost device, and the effect is that it can respond to changes in the transmitting and receiving level. is obtained.

It should be noted that the above-mentioned Examples show only examples of the present invention, and it goes without saying that the present invention should not be limited thereto.

[Effects of the Invention] As explained in detail above, according to the present invention, the standards regarding return loss among the PTT standards that differ in various countries around the world can be combined into one.
This has the remarkable effect that it is possible to realize a communication terminal device that satisfies the needs of only one piece of hardware.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an overview of the system configuration of a facsimile machine that is an embodiment of the present invention, and FIG. 2 is a diagram showing the main parts thereof.
FIG. 3 is a diagram showing a more detailed configuration example of the portion surrounded by broken lines in FIG. 2, and FIG. 4 is a diagram showing an example of the configuration of a four-line converter. FIG. FIG. 5 is a flowchart showing the operation of the embodiment, FIG. 6 is a diagram showing the system configuration of another embodiment of the present invention, and FIG. 7 is the main part of the return loss diagram. FIG. 8, which is a diagram showing a detailed configuration example of the standard compatible section, is an operation flowchart thereof. off-hook detection section, 20H relay, 3-dial pulse sending section, 4. Ringing detection section, 5.5A + transformer,
6: 2494 line conversion section, 7 modem, 8,8A system control section, 9: Return loss standard compatible section, 10 to 13
．． relay. Figure 4 (a) Figure 5 A blue: Reference is 600Q system B group: Riff, 12/s is network system. Figure 8

Claims (2)

[Claims] (1) Transmission/reception level correction means for switching a terminating resistor on the secondary side of a transformer that couples the line and modem in an electrically insulated manner, and further compensating for changes in attenuation caused by switching the terminating resistor. , a return loss standard corresponding section having a means for appropriately switching between groups of return loss standards. (2) Multiple circuits with equal impedance on the secondary side of the transformer that connects the line and modem in an electrically insulated manner, and with capacitors of a capacity corresponding to the return loss standard group. 1. A communication terminal device comprising: a return loss standard corresponding section having: and means for appropriately switching between groups of return loss standards.