发明名称 |
Continuity-checking network for telecommunication system |
摘要 |
A marker at a central-office terminal, controlling the establishment of connections between local subscriber lines and inter-office links via an associated line concentrator/distributor, includes a test-signal generator connected via a two-way coupler to an outgoing branch of an engaged link, a first signal receiver connected by the coupler to an incoming branch of that link, and a second signal receiver inserted in a normally balanced phantom circuit formed by incoming and outgoing branches of a local line communicating with the link. Upon the establishment of a connection including such a link between two subscriber lines served by respective central-office terminals, an alternating test signal generated at one terminal must be detected with a predetermined minimum threshold by the first receiver but not by the second receiver of the other terminal before message transmission over this connection can be initiated.
|
申请公布号 |
US4024359(A) |
申请公布日期 |
1977.05.17 |
申请号 |
US19760657263 |
申请日期 |
1976.02.11 |
申请人 |
SOCIETA ITALIANA TELECOMUNICAZIONI SIEMENS S.P.A. |
发明人 |
DE MARCO, FRANCO;RIGO, GUALTIERO |
分类号 |
H04M7/06;H04Q3/00;(IPC1-7):H04B3/46 |
主分类号 |
H04M7/06 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|