JPS648752A - Signal detection circuit for telephone set - Google Patents

Signal detection circuit for telephone set

Info

Publication number
JPS648752A
JPS648752A JP16444187A JP16444187A JPS648752A JP S648752 A JPS648752 A JP S648752A JP 16444187 A JP16444187 A JP 16444187A JP 16444187 A JP16444187 A JP 16444187A JP S648752 A JPS648752 A JP S648752A
Authority
JP
Japan
Prior art keywords
telephone set
output
comparator
detection circuit
state
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP16444187A
Other languages
Japanese (ja)
Inventor
Hideaki Hamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Priority to JP16444187A priority Critical patent/JPS648752A/en
Publication of JPS648752A publication Critical patent/JPS648752A/en
Pending legal-status Critical Current

Links

Landscapes

  • Monitoring And Testing Of Exchanges (AREA)

Abstract

PURPOSE:To easily detect the communication state of a telephone set and a call signal by providing a comparing means comparing a potential difference between trunk lines connecting to the telephone set and a state detecting means detecting the state of the comparing means. CONSTITUTION:When an output of a comparator 1 is at 'L' normally, it represents that the telephone set is not busy. When the output of the comparator 1 is normally at 'H', it represents that the telephone set is busy. However when the output of the comparator 1 is logic L, the instant the output goes to logic H synchronously, it is indicated that the telephone set is being called. Thus, a status detection circuit 2 decodes the output of the comparator 1 to easily detect the busy state of the telephone set and a call signal.
JP16444187A 1987-07-01 1987-07-01 Signal detection circuit for telephone set Pending JPS648752A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP16444187A JPS648752A (en) 1987-07-01 1987-07-01 Signal detection circuit for telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16444187A JPS648752A (en) 1987-07-01 1987-07-01 Signal detection circuit for telephone set

Publications (1)

Publication Number Publication Date
JPS648752A true JPS648752A (en) 1989-01-12

Family

ID=15793223

Family Applications (1)

Application Number Title Priority Date Filing Date
JP16444187A Pending JPS648752A (en) 1987-07-01 1987-07-01 Signal detection circuit for telephone set

Country Status (1)

Country Link
JP (1) JPS648752A (en)

Similar Documents

Publication Publication Date Title
JPS6416134A (en) Radio telephone system
JPS648752A (en) Signal detection circuit for telephone set
ES8705729A1 (en) Interswitch line circuit.
JPS57145466A (en) Switchboard
JPS5773554A (en) Button telephone set
JPS6469143A (en) Facsimile equipment
JPS6481494A (en) Pushbutton telephone master device
JPS6472651A (en) Calling system by character dial
JPS6464459A (en) Communication equipment
JPS6472693A (en) Key telephone system
JPS6430395A (en) Key telephone system
JPS57141167A (en) Calling bell ringing system of interphone
JPS57206150A (en) Calling system
JPS5242307A (en) Subscriber answering detection system
JPS56137762A (en) Setting or modifying device for abbreviated dial storage
JPS648755A (en) Conference communication equipment
JPS5341109A (en) Signal arrival detecting device for accessory unit with telephone set
JPS6427351A (en) Telephone system with interruption function
JPS5687963A (en) Detection system of incoming call
JPS57113670A (en) Telephone set
JPS57180261A (en) Digital tone receiver
JPS5620365A (en) Fault detection system
JPS5558660A (en) Ringing tone transmission system
JPS56123132A (en) Cordless telephone set
JPS56123139A (en) Cordless telephone set