1) Can be connected each other and become a system.
2) Its communication is very easy just through a LERAN button.

Description:

The wireless online smoke alarm PS-RM101RC can be included in a same system by a LEARN button. When one of the detectors emits the high frequency digital signal (433.92MHZ), the others receive the same signal and will alarm together to remind users to take measures. It's photoelectric smoke detector, no wire, easy operation and installation.

Specification:

1) Working voltage: DC9V(smoke testing) DC4.5V(transmission/Receiver3X1.5V battery)
2) Current: DC9V : average stand-by current≤10uA, average alarming current
≤ 20mA; DC4.5V: average working current ≤120 uA
3) Alarming decibel: ≥85dB/3m
4) Alarming LED: Red LED
5) LEARN LED: Red/Green LED
6) LEARN button & Test Button
7) Frequency: 433.92MHz
8) Transmission/Receiver distance:  60m(wide place)
9) Working temperature: -10~40°C

Certificate:
CE, EN14604, RoHs, R&TTE

The product picture: