PLC(Power line Carrier)
Yes, 2-wire system same as IP system.
100 m.
Usually should be over RVV2*0.75.
Yes, it can work with others by SIP.
Yes, each 290A can conncet 8 2-wire indoor monitors, and the 290A can be extrened by two 290AB. Each 290AB can also connect to 8 2-wire indoor monitors.
A group of 290A*1+290AB*2 can work with 24 2-wire indoor monitors. If the monitors are more than 24pcs, you can add one more group 290A and 290AB. The 290A has two RJ45 ports to connect to a network switch for communication with other groups. This is how 2-wire intercom system scales.
290A and 290AB are powered by DC48V adapter, the 290 master can be powered by both DC48V adapter and PoE switch, the 290 slave doesn't need extra power.
