Two pairs of photocells are always delivered together with Parklio Bollard device and connected to the control box using a UTP cable.
Every photocell has its own transmitter that must be installed on site depending on the Bollard desired position.
Transmitter is only sending signal to photocell (receiver) and breaking up line between transmitter and photocell results in blocking bollard extension which prevents damage to vehicles.
Transmitter are powered by regular AA batteries that are not included inside transmitter due to transport limits.
Batteries inside transmitter can last up to one year but it is recommended to be replaced every six months.