公开(公告)号：US4748657A

公开(公告)日：1988-05-31

申请号：US865759

申请日：1986-05-22

申请人： Will Rudd ,  Dennis McCullough

发明人： Will Rudd ,  Dennis McCullough

IPC分类号： H04M3/14 ,  H04M3/22 ,  H04M3/38

CPC分类号： H04M3/14 ,  H04M3/2272 ,  H04M3/38

摘要： A handset actuated signal intercept circuit is located in a telephone central office and connected to the tip and ring leads of a telephone subscriber line. The signal intercept is operated from central office subscriber line power, but draws so small a current that it is undetectable in normal telephone usage. When a subscriber handset is lifted, the signal intercept detects dial tone and initiates a timing interval of predetermined duration. If no dialing pulses or tones are detected during this interval, the central office channel and trunk which are seized by the initiation of dial tone, are then freed for use on other subscriber lines. Alternatively, if the subscriber line is not authorized for use with touch-tone equipment, the appearance of selected touchpad tones on the subscriber line during the predetermined interval following the initiation of dial tone will activate a gate, which produces an alternating current short across the tip and ring leads of the subscriber line, and prevents further touchpad tones from getting out from the subscriber line.

摘要翻译： 手机启动信号拦截电路位于电话中心局并连接到电话用户线的尖端和环形引线。 信号拦截由中心局用户线路电源进行操作，但是在正常的电话使用中，电流不足，无法检测到。 当用户手机被提升时，信号截距检测拨号音并启动预定持续时间的定时间隔。 如果在该间隔期间没有检测到拨号脉冲或音调，则由拨号音启动而占用的中心局信道和中继线被释放以用于其他用户线路。 或者，如果用户线路未被授权使用按键音设备，则在拨号音开始之后的预定间隔期间，用户线路上所选择的触摸板音调的出现将激活一个门，其产生跨越 用户线的尖端和环形引线，并且防止进一步的触摸板音从用户线路中出来。