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Patent Searching and Data


Title:
OPPOSITE STATION RESPONSE DETECTION SYSTEM
Document Type and Number:
Japanese Patent JPH0514940
Kind Code:
A
Abstract:

PURPOSE: To make it possible to detect the response of an opposite station by tones even when a response signal is not transmitted from the opposite station.

CONSTITUTION: This system is provided with a tone detection circuit 2 detecting the existence of the tone of the frequency preliminarily fixed within a central trunk 1, a tone detection circuit 3 detecting the existence of the tone other than this preliminarily fixed frequency and a means detecting the response of the subscriber of an opposite station based on the detection result of the existence of the two tones when the trunk is transmitted. The device detects tones (videotex switching instruction signal) incoming from a Captain network, etc., and defines them as the response of the opposite stations.


Inventors:
KOYAMA KAZUHIKO
Application Number:
JP18832091A
Publication Date:
January 22, 1993
Filing Date:
July 03, 1991
Export Citation:
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Assignee:
NEC CORP
International Classes:
H04M3/00; H04M11/00; H04Q1/30; H04Q1/44; H04Q3/58; H04Q3/62; (IPC1-7): H04M3/00; H04M11/00; H04Q1/30; H04Q1/44; H04Q3/58; H04Q3/62
Attorney, Agent or Firm:
Masaki Yamakawa