Impulse system are the traditional wire-bound time network and are frequently used in administration buildings, industry and public service, where there is a need for reliable and accurate control of time.

Westerstrand impulse driven clocks have a high resistance against disturbances in the network and will perform well in most existing cable nets.

This system make use of a 24VDC polar reversing impulse for the control and operation of connected clocks (often referred to as Slave Clocks). The impulses are distributed by Master Clocks, Master Clock Programmers or Time Centrals of various design and performance.

The impulses can be of 1/1-minute, ½-minute or 1/1-seconds type, depending on whether the clocks are with or without seconds hand. E.g. if the impulses are of 1/1-minute type, this means that the sending master will synchronize the connected clocks once every minute. Normally the clocks are connected in parallell to the master, using 2-wire cable.

At installation the time presently indicated by the connected Slave Clocks, is entered into the Master Clock, Master Clock Programmer or Time Central by programming. Thereafter the Master Clock will automatically set the clocks to indicate correct time by rapid impulsing. In case of power failure, the connected clocks will stop, but as soon as power returns they will automatically be set to correct time by rapid impulsing.