JP2003153317A - Terminal power supply system for key telephone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that in a conventional key telephone power supply system, the power supply circuit of the main unit side must be constituted of a power supply circuit assumed that the terminal having the largest power consumption is provided in the longest wiring length, and hence the power supply circuit is expensive. SOLUTION: The lowest voltage value of the terminal input end is detected when the power consumption of the key telephone terminal to be connected becomes maximum, the optimum power supply circuit is selected for the lowest voltage value and supplied. Thus, the suitable power supply can be controlled for the difference between the maximum power consumption due to the type of the key telephone or the like.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply method for a terminal such as a key telephone, and more particularly to a button operated by supplying power from a main unit such as a private branch exchange or a key telephone. The present invention relates to a power supply method for a telephone. 2. Description of the Related Art As a conventional example of a power supply system for a terminal such as a key telephone, as described in Japanese Patent Application Laid-Open No. 6-58972, for example, There is a technology to supply a high voltage. The prior art will be described with reference to the drawings. Each of the subscriber circuits 1a to 1n includes a subscriber circuit main body 8a to 8n,
Control circuits 9a to 9n for controlling these subscriber circuit bodies 8a to 8n, respectively, and built-in power supply circuits 6a to 6n connected thereto. Built-in power supply circuit 6a
6n generate the subscriber terminal power supply B and the low-voltage power supply V by receiving the power supply from the office power supply 11, and
Is supplied to each of the subscriber circuit bodies 8a to 8n,
A low-voltage power supply V is supplied to each of the control circuits 9a to 9n. The B voltage of each of the built-in power supply circuits 6a to 6n is
It is set arbitrarily according to the distance from 1. [0004] However, in the above-described power supply system, the power supply circuit on the main device side is configured on the assumption that a terminal having the longest wiring length and the largest power consumption is arranged. However, there is a problem that the price of the power supply circuit increases. [0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply system capable of reducing the price of a power supply circuit. According to the present invention, there is provided a power supply system for supplying power to a key telephone from a main unit having a plurality of power supply circuits, and detecting a power supply voltage at an input terminal of the key telephone. Means, a means for detecting a maximum power consumption of the key telephone, a voltage value required for operation of the key telephone from the power supply voltage and the maximum power consumption, and Means for selecting an optimal power supply circuit from the above and supplying power to the key telephone. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a power supply system for a key telephone according to an embodiment of the present invention. In this figure, a main unit 14 and a key telephone 15 of a key telephone are respectively provided with control units 1 and 9,
And control data circuits 3 and 8, and a cable 13
, And transmits and receives control data to constitute a key telephone device. The power supply circuit switch 7 in the main device 14 selects one circuit from the first power supply circuit 4, the second power supply circuit 5, and the third power supply circuit 6 and connects it to the cable 13. To supply power to the key telephone 15. The memory 2 stores various kinds of information such as minimum operating voltage information for each model of the key telephone 15, and the contents are read out by a request of the control unit 1. Next, the operation of this embodiment will be described. When the key telephone 15 is connected to the cable 13, the control unit 1 instructs the power supply circuit selection switch 7 to switch between the first power supply circuit 4, the second power supply circuit 5, and the third power supply circuit 6. To select the circuit with the highest power supply voltage,
Connect to cable 13. [0011] In the key telephone 15 supplied with power via the cable 13, the control unit 9 detects the model information of the key telephone different depending on the number of buttons and the like. The input voltage detection circuit 10 is connected to the main device 1 by the line resistance of the cable 13.
Then, the input terminal voltage of the key telephone 15 which is lower than the voltage supplied from the terminal 4 is detected. The detected model information and input terminal voltage are transmitted to the control unit 1 of the main device 14 via the control data transmission / reception circuit 8, the cable 13, and the control data transmission / reception circuit 3. The control unit 1 reads the maximum power consumption value of the model corresponding to the received model information of the key telephone from the memory 2 and determines the maximum voltage value effective at the input terminal when the key telephone consumes the most power. By calculating and subtracting the calculated value from the input terminal voltage of the key telephone 15 detected by the input voltage detection circuit 10, the lowest voltage value which may be lowest at the key telephone input terminal due to the power consumption of the key telephone is obtained. . Next, the control unit 1 reads out the minimum operating voltage information necessary for operating the key telephone in Seijo from the memory 2 and subtracts the minimum operating voltage information from the minimum voltage value so as to be necessary for the normal operation of the key telephone. The surplus voltage value for the minimum operating voltage is calculated. When the surplus voltage value is equal to or less than 0 V, the control unit 1 sends the input voltage at the keypad telephone input terminal to the display 11 via the control data transmission / reception circuit 3, cable 13, control data transmission / reception circuit 8, and control unit 9. Is insufficient, a warning is issued to the effect that the key telephone 15 will not operate normally when the power consumption is maximized. When the surplus voltage value is equal to or higher than 0 V, the control unit 1 selects one of the first power supply circuit 4, the second power supply circuit 5, and the third power supply circuit 6 from the key telephone 15 according to the surplus voltage value.
The power supply circuit necessary and optimal for the operation is selected and an instruction is issued to the power supply circuit selection switch 7. The power supply circuit selection switch 7 connects the designated power supply circuit to the cable 13 so that the key telephone 15 is appropriately supplied with power. It is also possible to directly input information from the KEY 12 and designate one power supply circuit from a plurality of power supply devices to supply power. As described above, according to the present invention, the lowest voltage value at the terminal input terminal when the power consumption of the connected key telephone apparatus terminal is maximized is detected. By selecting a power supply circuit most suitable for the lowest voltage value and supplying power, appropriate power supply control can be performed even for a difference in maximum power consumption depending on a model such as a key telephone. In each power supply circuit, an inexpensive one can be used, and as a result, the effect of reducing the price of the power supply circuit can be obtained.

[Brief description of the drawings] FIG. 1 is a block diagram showing an embodiment of the present invention. 1 control unit 2 memory 3 Control data transmission / reception circuit 4 First power supply circuit 5 Second power supply circuit 6. Third power supply circuit 7 Power supply circuit selection switch 8 Control data transmission / reception circuit 9 Control unit 10. Input power detection circuit 11 Display 12 KEY 13 Cable 14 Main unit 15 button telephone

Claims (1)

Claims: 1. A power supply system for supplying power to a key telephone from a main device having a plurality of power supply circuits, comprising: means for detecting a power supply voltage at an input terminal of the key telephone; Means for detecting the maximum power consumption of the telephone, calculating a voltage value required for the operation of the key telephone from the power supply voltage and the maximum power consumption, and selecting an optimum power supply from the plurality of power supply circuits. Means for selecting a circuit and feeding power to the key telephone.