The GA01P's input is a switch signal. When the input port is short-circuited to ground (GND), the GA01P send an alarm SMS to your pre-set alarm mobile phone or call a pre-set alarm number. The content of the alarm SMS can be customized. It is simple and convenient to use and can be easily embedded into other devices to function as a remote alarm system. The alarm content for the 1-channel alarm input and the alarm content for restoring normal operation can both be customized. Built-in rechargeable lithium battery, normally in charging state, provide power when the main power supply fails, sending alarm SMS to a preset number. 1. Remote SMS and telephone calls are possible. 2. Supports one alarm input channel. 3. Supports connection to an alarm device to achieve sound or audible/visual alarms. 4. Supports wide voltage input, DC 5V to DC 15V. (3) One audible alarm device (only for customer test samples or sound prompts during alarms; due to insufficient sound, customers need to purchase according to their own projects). (4) One built-in 3.7V rechargeable battery (provides power for SMS and telephone alarms during power outages; voltage output for audible alarms is not possible during power outages). Specifications: 4G (US version) Color: Black Material: ABS Package Contents: 1set * 4G GA01P GSM Smart Remote Power Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.