01. Working voltage: DC18V;
02. Working current 50mA-450mA;
03. 4"CRT or 4" LED;
04. Audio SNR:≥70dB;
05. Harmonic distortion: ≤5%;
06. Temperature: -10℃~+55℃;
07. Installation: Surface wall mount type;
08. Bi-directional talking;
09. Monitoring/Call/Talkback/Unlocking;
10. The doorbell and SOS interface;
11. Contrast&brightness is adjustable;
12. Release information (Optional);
13. 4 defense area alarm;
14. Suitable for M-2000.