Impulse is a conventional two-wired system carrying polarized impulses 12 V, 24V or 48 V.
This conventional two wired time distribution system, has been in use for decades, the control is carried out via pole-changing impulse. A 1-minute, ½-minute or 1-second impulse, transmitted via two-wire lines. Only time interval can be synchronized (absolut start time and date has to be set manually).