External Connection - Comelit RS485 Mode D'emploi

Power indicator: it show the present power status. Light on means power
connected well.
COMM indicator: when keyboard connect to dome camera or PTZ, this light is
on.

2.2 External Connection

Please read the user manual carefully before any connection. Any wrong
connection may cause the device damaged permanently. When you connect
the device, please make sure the power of all devices are off. Communication
cable used between the devices connection must be twisted-pair cable with
shielding. When cable is set up, high voltage line or other interfering line
should be avoided as much as possible. Keyboard cannot be
cross-connected when connecting with other communication devices. Anode
must be to anode, cathode to cathode. As shown below:
5