How many video door entry units 14550/20550 with 01963 and 01960 can I connect on a 2 fili/2 wire system?

For every 4 video door entry units with the home automation control unit 01960, you need to create an island with a divider 692S and power supply unit 6922. All the home automation control units must always each be powered by their own power supply unit 01801.

This rule need not be applied when all the video door entry units have only the 01963 (2 fili/2 wire interface) with no home automation control unit