JPH04246960A - Order telephone system - Google Patents

Abstract

PURPOSE:To make a call with a master station from any slave stations even if a line disconnection occurs in an order telephone line. CONSTITUTION:The order telephone line 18 whose one end is connected to a master station arrangement telephone board 11 sequentially connects the salve stations 191-194 and connects the other end of the line 18 to the master station arrangement telephone board 11. The line disconnection is detected in the line 18 by using a pilot signal generation part 15 and a pilot signal reception part 14. Then, a switch control part 16 opens/closes the switch of a switch part 17 in correspondence with the detection result.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone meeting system, and more particularly to a telephone meeting system having a loop-like line configuration.

0002

2. Description of the Related Art In a conventional meeting telephone system, as shown in FIG.
It is terminated with 4.

0003

[Problems to be Solved by the Invention] In this conventional meeting telephone system, for example, the slave station 232 and the slave station 233 in FIG.
When the meeting line 25 is disconnected between the slave stations 233 and 23
4 had the problem that it became impossible to talk to the master station.

0004

[Means for Solving the Problems] The meeting telephone system of the present invention includes a switch, one end connected to a master station, a plurality of slave stations sequentially connected, and the other end connected to the master station via the switch. A line, a line disconnection detection means for detecting line disconnection of the meeting line, and a switching control section that opens and closes the switch according to the detection state of the line disconnection detection means.

[0005] The line disconnection detection means includes a pilot signal sending unit that sends a pilot signal to the meeting line;
It may be configured to include a pilot signal receiving section that receives the pilot signal via the meeting line and outputs a signal indicating no reception to the switching control section when the pilot signal cannot be received.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

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

In FIG. 1, reference numeral 11 indicates a telephone board for meetings at the master station. 12 is the handset of the master station meeting telephone board 11;
91 to 194 are slave stations connected to the receiver 12.

[0009] The handset 12 is connected to the central terminal of the hybrid 13. One end of the meeting line 18 is connected to one of the terminals on both sides of the hybrid 13, and the meeting line 1
8, the slave stations 191 to 194 are sequentially connected. The other end of the meeting line 18 is connected to the hybrid 1 via the switching unit 17.
Connect to the remaining terminals of 3.

[0010] Normally, both switches of the switching section 17 are open. Pilot signals are transmitted from the two pilot signal generators 15 to both directions of the meeting line 18, and are received by the two pilot signal receivers 14, respectively. When the switching control section 16 receives a signal indicating no reception from the pilot signal receiving section 14, it issues a command to the switching section 17 to close the corresponding switch, thereby closing the switch.

[0011]

Effects of the Invention As explained above, the present invention returns the end of the meeting line that sequentially connects each slave station from the master station to the master station via a switch, and when a disconnection of the meeting line occurs, the switch is turned off. Since it is closed, it has the effect that even if the line is disconnected on the meeting line, any slave station can talk to the master station.

[Brief explanation of the drawing]

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

FIG. 2 is a block diagram of a conventional meeting telephone system.

[Explanation of symbols]

11　　　Master station meeting telephone board 12　　　　　Telephone receiver 13 Hybrid 14 Pilot signal receiving section 15 Pilot signal generation section 16 Switching control section 17 Switching section 18 Meeting line 191-194　　Slave station

Claims (2)

[Claims] 1. A switch, a meeting line whose one end is connected to a master station, a plurality of slave stations are sequentially connected, and the other end is connected to the master station via the switch, and a disconnection of the meeting line is detected. A meeting telephone system comprising a line disconnection detection means and a switching control section that opens and closes the switch according to the detection state of the line disconnection detection means. 2. The line disconnection detection means includes a pilot signal sending unit that sends out a pilot signal to the meeting line, and a pilot signal sending unit that receives the pilot signal via the meeting line and detects no reception when the pilot signal cannot be received. 2. The meeting telephone system according to claim 1, further comprising a pilot signal receiving section that outputs a signal to the switching control section.