KR20010058802A - Line off hook display telephone and control method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trunk line occupying status display telephone and a control method thereof. In the prior art, when two or more telephones simultaneously occupy a trunk line, the first user causes discomfort and the next user does not hear a dial tone. This is a mistake in the failure of the phone, there is a problem that can be tapped or stolen by other users, and, in the case of a telephone using a modem, there is a problem that the transmission and reception of data is interrupted by the occupation of another telephone. Therefore, the present invention was devised to solve the above-mentioned conventional problems, and by detecting whether the other telephone occupies the trunk line and displaying it to the user, at least two telephones simultaneously block the occupation of the trunk line. It prevents the occurrence of unpleasant feelings and prevents eavesdropping or theft by checking the occupancy of other users, and also prevents the transmission and reception of data by the occupancy of other phones when the phones using modems are connected in parallel. There is.

Description

CO line occupancy status display phone and its control method {LINE OFF HOOK DISPLAY TELEPHONE AND CONTROL METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trunk line occupying state display telephone and a control method thereof. In particular, in a telephone with a microcomputer, a trunk line occupying status indicating telephone and a device for detecting a display state of a trunk line before occupying the trunk line are displayed. It relates to a control method.

In general, most telephones widely used in homes and offices use public switched telephone networks, and in many cases, multiple telephones are connected in parallel on a single line.

Thus, when one phone is in use, it is often unpleasant to the user who was on the call first when a person who does not know it picks up the handset to use another phone connected in parallel.

Fig. 1 is a circuit diagram showing a configuration of a DC holding circuit in a conventional telephone, which includes a filter L1 (L2) for removing noise of an input / output signal as shown therein; A ring detector 10 for detecting the inflow of the ring signal through the trunk line; A hook relay 20 connected to the trunk line such that the telephone occupies the trunk line; A DC holding part 30 forming a loop of DC current flowing through the trunk line to separate DC current; It is composed of a transformer (40) for separating the alternating current flowing through the trunk line, the DC holding unit 30 includes a bridge diode (31) for converting the AC power into DC power; A constant voltage unit configured of a zener diode (ZD1), a resistor (R1) (R2), and a capacitor (C1) to convert the DC voltage of the bridge diode 31 into a constant voltage of a predetermined level and output the same; The darling tone part 32 which separates the DC current by the output signal of the constant voltage part is described in detail.

When a plurality of telephones are connected in parallel to one trunk line, first, when the user picks up the receiver while the other telephone does not occupy the trunk line, the hook relay 20 is closed to remove noise through the filters L1 and L2. The DC loop current is introduced into the DC holding unit 30, the user occupies the trunk line.

Therefore, when it is rectified by the bridge diode 31, the zener diode ZD1, the resistors R1, R2, and the capacitor C1 are applied to the darlington part 32 at a constant voltage, and the darlington part 32 Acts as a virtual inductor, which has a large inductance value, so only DC current flows.

However, when another telephone connected in parallel is using the CO line and the user picks up the receiver, the hook relay 20 is closed to allow the user to connect the CO line being used by another person.

Therefore, in the prior art, when two or more telephones occupy the trunk line at the same time, it causes discomfort to the first user and the next user is mistaken for the failure of the telephone due to the phenomenon that the dial tone is not heard. There is a problem that the user's trunk line eavesdropping or theft is possible, and, in the case of a telephone using a modem, transmission and reception of data is interrupted by the occupation of another telephone.

Accordingly, the present invention has been made to solve the above-mentioned problems, by detecting and displaying the state of use of the CO line in advance before occupying the CO line when the plurality of phones with a microcomputer are connected to the CO line in parallel. SUMMARY OF THE INVENTION An object of the present invention is to provide a trunk line occupation status indicating telephone and a control method thereof for preventing the occupation of a plurality of telephone lines.

1 is a circuit diagram showing the configuration of a DC holding circuit in a conventional telephone.

Fig. 2 is a circuit diagram showing the configuration of a DC holding circuit in the present invention.

3 is an operational flowchart of the microcomputer in FIG.

*** Description of the symbols for the main parts of the drawings ***

100: ring detector 110: hook relay

120: transformer 130: DC holding unit

131: bridge diode 132: constant voltage portion

133: Darlington unit 134: PC relay

135: photo coupler 140: hook switch

150: cd 160: memory

170: microcomputer R1 to R5: resistance

The configuration of the present invention for achieving the above object is a hook relay for connecting to the trunk line so that the phone occupies the trunk line; A transformer for separating an alternating current flowing through the trunk line; A DC holding unit which forms a loop of the DC current flowing through the trunk line to separate the DC current and detects and outputs a trunk line occupation state according to the level of the separated DC current; A hook switch for detecting on / off of the handset; An LCD for displaying a current phone state on a screen; A memory for storing trunk line status values; It is characterized in that it is configured as a microcomputer to control the operation of each unit, and determine and display whether the trunk line is occupied by other telephones by the output signal of the DC holding unit.

The present invention provides a first step of setting a basic state value if not determined by determining whether a basic state value of a trunk line is set; A second step of determining whether the trunk line is in use if the basic state value is set in the first step and displaying the same if the basic state value is in use; A third step of determining whether to continue to use the trunk line when the operation of the first to second steps is completed; If it is not in use in the second step or will continue to use in the third step, characterized in that the fourth step of the off-hook to end after the call.

Hereinafter, with reference to the accompanying drawings, the operation and effect of an embodiment of the present invention will be described in detail.

Fig. 2 is a circuit diagram showing the configuration of the DC holding circuit in the trunk line occupying state display telephone of the present invention, as shown therein; a filter (L1) (L2) for removing noise of an input / output signal; A ring detector 100 for detecting the inflow of the ring signal through the trunk line; A hook relay 110 connected to the trunk line such that the telephone occupies the trunk line; A transformer 120 for separating the AC current flowing through the trunk line; A DC holding unit 130 forming a loop of DC current flowing through the trunk line to separate the DC current and output voltages of different levels according to the DC current level on the trunk line; A hook switch 140 for detecting on / off of the handset; LCD (150) for displaying the current state of the phone on the screen; A memory 160 for storing basic state values of the trunk line; After controlling the operation of each unit, and set the DC current in the state that does not occupy the trunk line as the default state value, it is determined whether the trunk line is occupied by other telephone according to the output voltage level of the DC holding unit 130 A microcomputer 170 displayed on the LCD 150 is configured.

The DC holding unit 130 includes a bridge diode 131 for converting AC power into DC power; A constant voltage unit 132 composed of a zener diode (ZD1), a resistor (R1) (R2), and a capacitor (C1) to convert the DC voltage of the bridge diode 131 into a constant voltage of a predetermined level and output the same; A darling tone part 133 separating the direct current from the output signal of the constant voltage part 132; A current path control relay 134 for selecting a DC current path under the control of the microcomputer 170; A resistor (R3) for forming a current path by the DC current output from the PC relay (134); A resistor (R4) for forming another current path for detecting a trunk line occupation state by a DC current output from the CPC relay (134); A photocoupler 135 for outputting a voltage having a different level according to the DC current level of the darlington part 133 input through the resistor R4; And a pull-up resistor (R5) for pulling up the output end of the photo coupler 135, wherein the resistor (R3) is selected in the range of several tens to several tens of ohms so as to have a DC resistance value conforming to a communication device standard, (R4) is selected in the tens of kHz area to have a higher resistance value than the resistor (R3), will be described in detail with reference to Figure 3 attached to the operation process according to the present invention configured as described above.

First, when the user lifts the handset (S1), the hook switch 140 operates to notify the microcomputer 170, and the microcomputer 170 operates the hook relay 110 to operate the filters L1 and L2. The DC loop current from which the noise is removed is introduced into the DC holding unit 130 to occupy the trunk line.

Then, the microcomputer 170 determines whether the basic state value of the trunk line is set (S2). If the basic state value is not set, it is determined whether to set it (S3) and sets the basic state value.

At this time, the setting of the basic state value is a DC voltage rectified through the bridge diode 131 in the state that the main line is not occupied by the zener diode (ZD1), resistor (R1) (R2) and capacitor (C1) as a constant voltage. When the rectification is applied to the darlington part 133, the darlington part 133 which receives the input is operated as a virtual inductor to have a large inductance value, so that only the DC current is controlled by the PC 170. ) Is output to the resistor (R4).

In addition, since the resistance value of the resistor R4, which is a path of the current, is set to have a high resistance value, the microcomputer 170 that receives the DC current value at this time as the voltage value through the photo coupler 135 stores the memory 160 as a default state value. ).

Then, it is determined whether to continue to use the trunk line (S7) when not in use, the receiver is terminated (S10), or if you continue to use, the microcomputer 170 controls the PC relay 134 to Darlington unit 133 The DC voltage flowing through is applied to a resistor (R3) having a resistance value selected to meet the current standard recognized by the exchange, and occupies the trunk line (S8) and makes a call.

However, when the basic state value of the trunk line is stored in the memory 160, the microcomputer 170 that receives the DC current value of the current trunk line through the photo coupler 135 compares it with the basic state value. (S5) If it is the same, it is determined that it is not in use, and if it is not the same, it is determined that the current CO line is in use.

If it is determined that there is no other user on the CO line as the basic state value, the user off-hooks the call, and when another phone connected in parallel is using the CO line, the microcomputer 170 currently makes a CO line through the CD 150. Indicates that this is in use.

If it is determined that the trunk line is to be used continuously (S7), when not in use, the receiver is placed and terminated (S10), or if it is to be continued, the microcomputer 170 off-hooks to make a call and then terminates.

As described in detail above, the present invention detects whether the other telephone occupies the trunk line and displays it to the user, and at the same time, two or more telephones block the occupation of the trunk line, thereby preventing the first user from causing discomfort. By checking the occupancy of the user's trunk line to prevent eavesdropping or theft, it is also effective to prevent the transmission and reception of data by the occupation of another phone when the phone using the modem connected in parallel.

Claims (7)

A hook relay connected to the trunk line such that the telephone occupies the trunk line; A transformer for separating an alternating current flowing through the trunk line; A DC holding unit which forms a loop of the DC current flowing through the trunk line to separate the DC current and detects and outputs a trunk line occupation state according to the level of the separated DC current; A hook switch for detecting on / off of the handset; An LCD for displaying a current phone state on a screen; A memory for storing trunk line status values; And a microcomputer configured to control the operation of each unit and determine and display whether the trunk line is occupied by another telephone by the output signal of the DC holding unit. The semiconductor device of claim 1, wherein the DC holding unit comprises: a bridge diode configured to convert AC power into DC power; A constant voltage unit configured of a zener diode, first and second resistors, and a capacitor to convert the DC voltage of the bridge diode into a constant voltage of a predetermined level and output the constant voltage; A darlington part for separating a DC current by the output signal of the constant voltage part; A CPC relay configured to select and output a DC current path under the control of a microcomputer; A third resistor forming a current path by the direct current output from the CPC relay; Forming a different current path for detecting the occupation of the trunk line by the DC current output from the CPC relay, characterized in that consisting of a voltage output unit for outputting a different level of voltage according to the level of the DC current CO line occupancy status display phone. 3. The apparatus of claim 2, wherein the voltage output unit comprises: a resistor forming another current path by direct current; A photocoupler configured to output voltages having different levels according to the level of the DC current input through the resistor; A trunk line occupation status indicating telephone comprising: a pull-up resistor configured to pull up an output end of the photo coupler. The method of claim 2 or 3, wherein the third resistor is selected in the range of several tens to several tens of voltage so as to have a DC resistance value conforming to a communication device standard, and the resistance in the voltage output unit is higher than the third resistance. A telephone line occupancy status display telephone, characterized in that selected from several tens of ㏀ areas. Determining whether a basic state value of the trunk line is set, and if not, setting a basic state value; A second step of determining whether the trunk line is in use if the basic state value is set in the first step and displaying the same if the basic state value is in use; A third step of determining whether to continue to use the trunk line when the operation of the first to second steps is completed; If not in use in the second step or continue to use in the third step, off the hook and the end of the call after the call comprises a fourth step of controlling the occupation line occupancy status telephone. The method of claim 5, wherein the setting of the basic state value of the first step comprises determining whether to set the basic state value, and setting the DC current value of the state where the trunk line is not occupied as the basic state value, and then determining whether to continue to use the basic state value setting operation. And performing a fourth step of performing an operation of the third step and ending after the call by off-hooking if the basic state value is not set. The method of claim 5, wherein the operation of determining whether the CO line is in use comprises comparing the set basic state value with the DC current value of the current CO line to determine that the CO line is not in use, and determining that the CO line is currently in use. A control method for a trunk line occupation status display telephone.