JPH0398552U - - Google Patents
Info
- Publication number
- JPH0398552U JPH0398552U JP744390U JP744390U JPH0398552U JP H0398552 U JPH0398552 U JP H0398552U JP 744390 U JP744390 U JP 744390U JP 744390 U JP744390 U JP 744390U JP H0398552 U JPH0398552 U JP H0398552U
- Authority
- JP
- Japan
- Prior art keywords
- connection device
- external connection
- loop
- line
- detection circuit
- 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.)
- Granted
Links
- 238000001514 detection method Methods 0.000 claims description 7
- 230000002265 prevention Effects 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 claims 2
- 238000010586 diagram Methods 0.000 description 1
Description
第１図は、本考案の一実施例を示すブロツク図
である。
３……共鳴り防止機能付電話回線使用中表示器
、１０……第１ループ検出回路、２０……第２ル
ープ検出回路、３０……回線切断回路、４０……
回線使用中表示出力回路、５０……制御回路。
FIG. 1 is a block diagram showing one embodiment of the present invention. 3... telephone line in use indicator with resonance prevention function, 10... first loop detection circuit, 20... second loop detection circuit, 30... line disconnection circuit, 40...
Line in use display output circuit, 50... control circuit.
Claims (1)
続され、上記第１外部接続装置側が直流ループを
形成していることを検出する第１ループ検出回路
と； 上記第１外部接続装置の下部に接続される第２
外部接続装置と上記第１外部接続装置との間に接
続され、上記第２外部接続装置が直流ループを形
成していることを検出する第２ループ検出回路と
； この第２ループ検出回路と上記第２外部接続装
置との間に接続され、回線を切断する回線切断回
路と； 上記第１外線接続装置が直流ループを形成して
いることを示す信号を上記第２外部接続装置に出
力する回線使用中表示出力回路と； 上記第１ループ検出回路が直流ループ形成を検
出し、上記第２ループ検出回路が直流ループ形成
を検出していないときに、上記回線切断回路を動
作させるとともに上記回線使用中表示出力回路を
動作させる制御回路と； を有することを特徴とする共鳴り防止機能付外線
使用中表示器。[Claims for Utility Model Registration] A first loop detection circuit that is connected between an outside line of a telephone line and a first external connection device, and detects that the first external connection device side forms a DC loop; A second external connection device connected to the lower part of the first external connection device.
a second loop detection circuit connected between an external connection device and the first external connection device, the second loop detection circuit detecting that the second external connection device forms a DC loop; a line disconnection circuit that is connected between the second external connection device and disconnects the line; a line that outputs a signal indicating that the first external connection device forms a DC loop to the second external connection device; In-use display output circuit: When the first loop detection circuit detects the formation of a DC loop and the second loop detection circuit does not detect the formation of a DC loop, the line disconnection circuit is operated and the line is not in use. A control circuit for operating an internal display output circuit; and an external line in use display with a resonance prevention function.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP744390U JPH0644204Y2 (en) | 1990-01-29 | 1990-01-29 | Telephone line busy display with resonance prevention function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP744390U JPH0644204Y2 (en) | 1990-01-29 | 1990-01-29 | Telephone line busy display with resonance prevention function |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0398552U true JPH0398552U (en) | 1991-10-14 |
| JPH0644204Y2 JPH0644204Y2 (en) | 1994-11-14 |
Family
ID=31511101
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP744390U Expired - Lifetime JPH0644204Y2 (en) | 1990-01-29 | 1990-01-29 | Telephone line busy display with resonance prevention function |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0644204Y2 (en) |
-
1990
- 1990-01-29 JP JP744390U patent/JPH0644204Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0644204Y2 (en) | 1994-11-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |