JPS5890895A - Monitor system for outgoing and incoming trunk polarity for automatic exchange - Google Patents

Abstract

PURPOSE:To normally operate the line, even if there is a mistake in the connection of a main trunk, by inverting an output signal of the polarity change detection means, if a call signal is not detected for a prescribed time after the detection of the polarity change in the main trunk. CONSTITUTION:With a main trunk (not shown) in vacant state, when a comparator 5 connected to main trunks A, B detects the change in the polarity of the main trunks, a time limit circuit 9 is started via an EXOR6 and an AND7. The said circuit 9 generates a high level signal for a prescribed time to a terminal X after starting and displays the state of busy trunk to a central control unit CCU from an AND8. When a call signal detection circuit 4 detects a call signal within the said prescribed time, the signal displays an incoming call to the CCU and suppresses the output of the X terminal of the circuit 9. If no call signal comes, the terminal X of the circuit 9 gives an output after a prescribed time, the said output is latched in matching with the output state of the comparator 5 and the state is displayed on the CCU via an EXOR12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ingress/egress trunk polarity monitoring system in an automatic switchboard.

Conventionally, in the ingress/egress trunk of an automatic switchboard (hereinafter referred to as CBWT), the polarity of the game is generally such that when the CBWT is empty, All is the battery and B line is earth air, and when a call is received, the polarity is reversed and the B line is In the 9CBWT, collision prevention was implemented (by restricting or disabling outgoing calls).

For this reason, even if the A and B lines of the CBWT are connected in accordance with the polarity of the central office telephone line during the initial construction of an automatic private branch exchange (hereinafter referred to as PABX), the cable between the central office and the PABX may be Kensuyo sim line.

If the BII is reversed, the CBWT corresponding to that line
After that, the line was blocked and outgoing calls were restricted, and the line became a dedicated line for incoming calls.

The gt diagram is a block diagram of the polarity monitoring circuit of a conventional CBWT.As shown in Figure 1, the polarity of one communication line is directly detected by the comparator circuit 2, passed through the AND circuit 3, and sent to the B8Y lead to the central control unit (CCU). )K sent. For Jin, Mu@B
@t) If the polarity is reversed.

In the meantime, the B8Y lead will display a busy status, and the CCU will recognize this and block the trunk. In addition,
In FIG. 1, ``@Trunk Empty/Busy Identification Signal'' is a signal indicating the usage status in the trunk, with a high level indicating empty and s'' low level indicating a busy (used) status.

Further, the IC is a lead that sends a low level signal to the CCU when a call signal detection circuit 1 detects an incoming call.

In response to this, a method was adopted to detect this line failure and display an alarm, but this still meant that calls could not be made while maintenance personnel were absent.

The purpose of the present invention is to solve the above-mentioned drawbacks without impairing the collision prevention function of the CBWT, and to provide a CBWT that can make and receive calls without any trouble regardless of the polarity of the line between one station and the PABX.
This provides a polarity monitoring method.

According to the present invention, there is provided a means for detecting the polarity of one communication line, and a means for detecting the polarity of one communication line, and when a calling signal is not received from the other station within a predetermined time after the polarity of the communication line changes when an ingress/egress trunk is empty, the An ingress/egress trunk polarity monitoring system is obtained, characterized in that it comprises means for inverting the output signal of the polarity detecting means.

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

Fig. 2 is a block diagram of one embodiment of the present invention, and Fig. 3 is a block diagram of an embodiment of the present invention.
FIG. 3 is a waveform diagram showing the operation of the circuit shown in the figure. 4 in Figure 2
5 is a calling signal detection circuit, and 5 is a comparison circuit.

6 is an exclusive off circuit, 7 and 8 are AND circuits,
9 is a timer circuit, IO is an OR circuit, 11 is a D-type flip-flop circuit, and 12 is an exclusive NOR circuit.

The polarity of the communication line (Fig. 3 (ml, (b)) is detected by the comparator circuit 5. The output of this comparator circuit 5 (Fig. 3 (C)) and the output are composed of C and R. If the exclusive OR circuit 6 calculates the exclusive OR with the signal obtained through the delay circuit 13, the delay time due to C and RK (T shown in FIG. 3) after the output of the comparison circuit 5 changes is obtained.
Only then, a high level 0 output (FIG. 3(d)) appears in the exclusive off circuit 6. It is well known that the same result is obtained whether the output of the comparator circuit 5 changes to high level 0 or low level (L). This detects whether the polarity has changed 〇The trunk empty/busy identification signal is a signal that can be identified within the trunk, as in the case of Figure 1, and is high level 0 when empty. Make sure that it becomes . Therefore, when the trunk is empty and the polarity of the central office line changes, the output of the AND circuit 7 (
FIG. 3(e)) is interrupted at time T1 and the timer circuit 9 is activated. When activated, this time limit circuit 9 is activated for a predetermined time (T2 in FIG. 3), which in this case is sufficiently longer than the intermittent time of the calling signal sent from the station. , outputs a low level (L) signal to the Y terminal (FIG. 3(g)). Trunk empty/busy identification signal and Y
When the terminal output is added to the ant circuit 8, the AND circuit 8
The output B8Y (Fig. 3 (h)) is connected to CC through the lead.
The busy status of the trunk is displayed on U, and the CCU identifies this and blocks this trunk as in the case of FIG.

On the other hand, the X terminal output (FIG. 4(f)) of the first time limit circuit 9 outputs a positive pulse if the calling signal does not arrive within the above-mentioned fixed time T8 and the polarity inversion is connected. When a signal arrives, the call signal detection circuit 4 detects the incoming call and sends a low level (L) signal to the CCU through the IC lead 11. The incoming call is displayed on the CCU, and the X of the time limit circuit 9 is sent.
Reduce terminal output.

Prevent positive pulses from being generated.

No call signal comes within a certain period of time T2 after the polarity change.

In addition, if the polarity reversal continues, a positive pulse output (FIG. 3(f)) appears at the X terminal of this timer circuit 9, and passes through the OR circuit 10 (FIG. 3(i)). The state of the D input terminal of the flip-flop circuit 11, that is, the state of the output of the comparator circuit 5 a certain period of time after the polarity change is doubled to the output Q. In other words, this indicates the state of the comparator circuit 5 after the polarity change.

The output Q of this flip-flop circuit 11 (FIG. 3 shows a high level of 0), and if no calling signal comes for a certain period of time after the polarity change, this state will be identified as normal polarity.

In this state, if the output of the comparator circuit 5 (FIG. 3(C)) further changes temporarily, the output 12 of the flip-flop circuit 11 (FIG. 3(k)) changes to low level (L) and the polarity is reversed. It will be displayed on the CCU.

In FIG. 2, the initial setting signal is a signal for latching the initial state of the incoming line B into the 7-lip-flop circuit 11 immediately after the PABX is powered on.

A high level I signal appears only immediately after the power is turned on.

The rest is the low level (TT of Ll).

As a result, if the polarity changes and this state persists even after a certain period of time has elapsed, this state is considered normal and the blockage for outgoing calls is also released. moreover.

Even if the polarity changes thereafter, the information can be displayed on the CCU without any problem.

Note that FIG. 3 shows the case where no calling signal is received and the trunk is empty, that is, when the output of the calling signal detection circuit 4 and the trunk empty/busy identification signal are both at high level ■. .

As explained above, the present invention provides A1 in the ingress/egress trunk.
Even if 1l and B@ are connected in reverse, after a certain period of time.

Outgoing calls are processed normally! , it becomes possible to prevent invalid occlusion.

FIG. 3 is a block circuit diagram showing one embodiment of the invention, and FIG. 3 is a waveform diagram of each part of FIG. 2.

1.4... Calling signal detection circuit, 2,5...
...Comparison circuit, 3,7.8...AND circuit, 6
・・・・・・Excl, -Sive-OR circuit, 9...
...Timed circuit, 10...OR circuit, 11...
...D type flip-flop circuit, 12...15. Exclusive Noah circuit, IC...Information lead indicating that there is an incoming call, BAY...Information lead indicating the 9th call of the incoming/outgoing trunk, REV...Information lead of the central office line Information lead indicating polarity.

Claims (1)

[Claims] means for detecting the polarity of the telephone line, and a call signal to the player is received within a predetermined time after the polarity of the telephone line changes when the ingress/egress trunk is empty;