Manually-activated timer for telephone subscriber - has depressible rod returned after given interval to operate alarm

摘要

The timer is employed by a telephone user, to provide an alarm signal after a given interval has elapsed, so that the duration of the call can be regulated. It is set into operation by depression of a rod, which is returned into its initial position at the end of the timer interval, causing an alarm signal to be provided. Pref. the alarm signal is provided at the end of a selected interval, e.g. with markings along the rod allowing it to be depressed by an amount corresponding to the required interval. The timer housing pref. has a regular geometric form, e.g. cylindrical rectangular or polygonal.