For the 6600 Series, how many different types of configuration are there and when do I use them?

The video door entry modules and intercoms in the 6600 Series can be programmed in two ways: The "master" configuration is used to program the "main" video door entry module (or intercom) in the system. A video intercom is defined as "main" when: - it is the only Video intercom or Intercom unit in the system. - for a call which is connected to multiple video door entry units: one of them will be identified as "master" and the other (connected to the same call) as "secondary". The "slave" configuration is therefore used to program the "secondary" video intercoms or intercoms.