JPS587105B2 - Terminal startup method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for activating a terminal device connected in parallel with a telephone connected to a telephone line.

When this type of terminal device is activated via a telephone line, since a telephone is connected in parallel to the terminal device, the bell of the telephone may also ring at the same time.

An object of the present invention is to provide a method for activating a terminal device without ringing a telephone bell when activating the terminal device.

The terminal activation method of the present invention includes means for reversing the polarity of the communication path when starting the terminal device, a current limiting resistor that suppresses the current flowing through the communication path to a constant current when the polarity is reversed, and a resistance of the current limiting resistor. A means for changing the value in a time-limited and step-by-step manner is provided, and the resistance value of the current-limiting resistor is changed in a time-limited and step-by-step manner within the current value of the telephone bell that does not ring when the polarity is reversed, so that the telephone bell rings. It is characterized by reversing the polarity in a short time and starting the terminal.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

In the figure, OSC is an oscillator, CC is a counter circuit, DV is a drive circuit, RO to Rn are current limiting resistors, st', st
2 is the contact of the terminal device starting relay, rv', rv2 is the contact of the RVJ relay for polarity reversal (not shown), RA is the resistor for protecting the rv contact, SWF is the automatic telephone exchange, TEL is the telephone, M is the terminal device. show.

As shown in the figure, the ordinary telephone TEL has the polarity of the L1 line and the L2 line θ, and the capacitor C in the telephone TEL is also charged with the same polarity.

At this time, the terminal device M has not been activated yet.

Next, when starting up the terminal device, a starting relay ST (not shown) is first activated based on the terminal device starting information.

The st1 contact opens due to the operation of the STJ relay, making the current limiting resistors RO to Rn of the communication circuit high resistance, and s
The t2 contact starts the counter circuit (C.C.).

Furthermore, when the ST relay operates, the RV relay (not shown) also operates, and the polarity is reversed by the rv' and rv2 contacts.

At this time, 2E (V) of the voltage E (V) charged in the capacitor C in the telephone TEL and the power supply E (V) is the voltage E (V) charged in the capacitor C in the telephone TEL.
It joins the bell coil inside L.

Therefore, at first, the current is limited by high resistance using current limiting resistors RO to Rn, and after a certain period of time tl, the capacitor C in the telephone TEL becomes E, (v) due to discharge, and the telephone TEL
The voltage applied to the bell coil inside is E+Et (V).

Next, the current limiting resistor R is set by mrQ in the drive circuit DV.
By short-circuiting O, the current is limited by the current limiting resistors R1 to Rn, and after a certain period of time t2, the capacitor C in the telephone TEL becomes E2 (V) due to discharge, and the telephone TEL becomes E2 (V).
The voltage applied to the bell coil in L is E+E2.

Furthermore, current limiting resistors RO and R1 are short-circuited by mr1 in the drive circuit DV.

As mrn in the drive circuit DV, which short-circuits the current limiting resistor at regular intervals, operates, the ST relay (not shown) is restored, and the terminal device M is activated by reversing the polarity.

As described above, by sequentially shorting the current limiting resistors at certain fixed time intervals, a constant current circuit is created and the telephone bell does not touch the current.
It can be activated by the polarity of the L2 line (1).

Next, when restoring, first the start relay SU (not shown) operates according to the terminal device recovery information, and when the STJ relay operates, the st1 contact connects to the current limiting resistor R of the communication circuit.
O to Rn are set to high resistance, and the counter circuit is activated by the st2 contact.

Further, the RV relay (not shown) is restored by the ST relay operation.

When the RV relay is restored, the polarity is restored using the rv1 and rv2 contacts.

Thereafter, the current limiting resistor is short-circuited at certain fixed time intervals in the same way as at startup, and the polarity can be restored using the constant current circuit.

Further, FIG. 2 shows changes in the potential of the L2 line as seen from the L1 line when the terminal device is activated.

A is at startup, and B is at recovery.

The figure shows the case of 10 steps, but as can be seen from the figure, the more steps there are, the more linear the change will be, and the better the results will be obtained.

As explained above, the present invention causes a telephone bell to ring by creating a constant current circuit by changing the resistance value of the current limiting resistor that suppresses the current flowing through the communication path to a constant current value in a time-limited and stepwise manner when the polarity is reversed. This has the effect of allowing the terminal device to start up without any delay.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing potential changes in the L2 line as seen from the L1 line when the terminal device is activated. OSC is an oscillator, CC is a counter circuit, DV is a drive circuit, RO to Rn are current limiting resistors, st1, st2 are contacts of a start information receiving relay ST (not shown), rv1,2
is the contact of the polarity reversal relay RV (not shown), and RA is r
Protective resistance of v' contact, SWF is automatic telephone exchange, TEL
is a telephone, M-Pa terminal device.

Claims (1)

[Claims] 1. In an automatic telephone exchange, means for reversing the polarity of the communication path, a current limiting resistor that suppresses the current flowing through the communication path to a constant current value when the polarity is reversed, and a means for changing the resistance value of the current limiting resistor in a time-limited and step-by-step manner. A terminal activation method characterized by providing a means for changing the polarity of the terminal device and activating the terminal device without ringing a telephone bell.