| 发明名称 |
DIAL-TONE-FIRST COIN TELEPHONE CIRCUIT IN WHICH STATION GROUND IS ISOLATED FROM THE CIRCUIT EXCEPT DURING SIGNALING FROM THE CENTRAL OFFICE |
| 摘要 |
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| 申请公布号 |
US3627950(A) |
申请公布日期 |
1971.12.14 |
| 申请号 |
USD3627950 |
申请日期 |
1969.10.07 |
| 申请人 |
BELL TELEPHONE LABORATORIES INC. |
发明人 |
WILLIAM C. SAND |
| 分类号 |
H04M17/02;(IPC1-7):H04M17/02 |
主分类号 |
H04M17/02 |
| 代理机构 |
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代理人 |
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| 主权项 |
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| 地址 |
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