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JPS6468196A - Trunk line interface circuit - Google Patents

Trunk line interface circuit

Info

Publication number
JPS6468196A
JPS6468196A JP22575787A JP22575787A JPS6468196A JP S6468196 A JPS6468196 A JP S6468196A JP 22575787 A JP22575787 A JP 22575787A JP 22575787 A JP22575787 A JP 22575787A JP S6468196 A JPS6468196 A JP S6468196A
Authority
JP
Japan
Prior art keywords
incoming
signal
trunk line
circuit
line
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
JP22575787A
Other languages
Japanese (ja)
Inventor
Hiroshi Oyama
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.)
NEC Corp
Original Assignee
NEC 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 NEC Corp filed Critical NEC Corp
Priority to JP22575787A priority Critical patent/JPS6468196A/en
Publication of JPS6468196A publication Critical patent/JPS6468196A/en
Pending legal-status Critical Current

Links

Landscapes

  • Sub-Exchange Stations And Push- Button Telephones (AREA)

Abstract

PURPOSE:To obtain an incoming tone synchronously with a trunk line incoming signal by sending an incoming tone from an incoming sound source to a sound signal line by a switch synchronously with an incoming signal from a trunk line through the provision of an incoming sound source so as to have only to connect the pushbutton telephone set rung by an incoming tone and an internal voice switch. CONSTITUTION:An incoming signal detection circuit 2 detecting an incoming signal from a trunk line is connected to a trunk line connection terminal 1 connecting a 2-wire analog trunk line in a trunk line interface circuit. A signal outputted from the incoming detection circuit to a signal line 12 is used as the control signal for the analog switch 8. When an incoming signal exists, the analog switch 8 is closed by the control signal on the signal line 12 and the incoming tone from the incoming sound source 7 is sent to a mix circuit 9. On the other hand, a 2/4-wire converting circuit 6 sends the voice signal on the 2-wire analog trunk line to the signal line 10 and gives it to the mix circuit 9. The mix circuit 9 mixes the signals. The output of the circuit 2 is scanned by a microprocessor of an interface circuit.
JP22575787A 1987-09-09 1987-09-09 Trunk line interface circuit Pending JPS6468196A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP22575787A JPS6468196A (en) 1987-09-09 1987-09-09 Trunk line interface circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP22575787A JPS6468196A (en) 1987-09-09 1987-09-09 Trunk line interface circuit

Publications (1)

Publication Number Publication Date
JPS6468196A true JPS6468196A (en) 1989-03-14

Family

ID=16834341

Family Applications (1)

Application Number Title Priority Date Filing Date
JP22575787A Pending JPS6468196A (en) 1987-09-09 1987-09-09 Trunk line interface circuit

Country Status (1)

Country Link
JP (1) JPS6468196A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02272993A (en) * 1989-04-14 1990-11-07 Canon Inc Private branch exchange
JPH02279095A (en) * 1989-04-20 1990-11-15 Canon Inc Key telephone system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02272993A (en) * 1989-04-14 1990-11-07 Canon Inc Private branch exchange
JPH02279095A (en) * 1989-04-20 1990-11-15 Canon Inc Key telephone system

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