GF-808 Wired Non-visual Single-family Intercom Doorbell Functions: 1. Two-way intercom and unlock function. 2. Two-core wire connection, four-core wire connection with unlock. 3. The door machine is surface-mounted design and easy to install. 4. Using new ABS plastic, durable. 5. There is an excellent side tone cancellation circuit, and the intercom sound is clear. 6. Effective intercom distance is more than 100 meters. 7. Easy installation, users can install it by themselves. Power parameters: 1. Audio undistortion rate> = 50mW 2. Talk time: unlimited, free call 3. Power adapter input voltage: AC 220V 50Hz 4. Power adapter output voltage: AC 12V 1200mA 5. Frequency response: 300-3400Hz +- 3dB 6. Working voltage: DC 12V +- 10% 7. Power consumption: static <0.2W, call status <2W 8. Installation: Hands-free wall mount 9. Indoor extension size: 227x87x45mm 10. Door machine size: 100x36x73mm