It is an infrared-sensing alarm.
Using GSM SIM card.
The alarm automatically binds itself with the last cell phone No. which calls it and holds for more than 20 seconds.
You are highly suggested use brand new cell phone No. (GSM SIM card) in the alerm, and NOT let anybody else know the No., in order to prevent the alerm from binding itself with other numbers.
Send "1111" to the alarm, from the binded cell phone No., to activate the infrared sensing funtion, and send '0000' for turning off.
It alerts when it senses infrared, like that released from human body or animals, for more than 5 seconds.
It will alert again in the next 3 ~ 5 minutes when it senses infrared continuously or again.
You can hear the sounds occur within about 10 meters around the alerm by Calling and holding it from the binded cell phone No.