发明名称 |
Key telephone system paging lockout circuit |
摘要 |
The telephone system includes N line paging lockout printed circuit cards, where N is equal to an integer greater than one. Each of the paging lockout cards includes a first relay controlled circuit to lockout (N-1) of the paging lockout cards from a paging amplifier if any of the (N-1) of the paging lockout cards attempts to initiate a paging operation a fraction of a second after one of the N paging lockout cards has initiated a paging operation. A second relay controlled circuit applies a busy tone to a telephone subset associated with each of the (N-1) of the paging lockout cards attempting to initiate a paging operation after the one of the N paging lockout cards has initiated a paging operation.
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申请公布号 |
US4144415(A) |
申请公布日期 |
1979.03.13 |
申请号 |
US19770863491 |
申请日期 |
1977.12.22 |
申请人 |
INTERNATIONAL TELEPHONE & TELEGRAPH CORP. |
发明人 |
SAXON, B. RONALD |
分类号 |
H04M11/02;(IPC1-7):H04M1/72;H04M1/70 |
主分类号 |
H04M11/02 |
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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