When a base station and accessories are bought individually they are not programmed to work with each other.
You need to purchase the programmer: 7T-PROGRAMME - http://www.internet-security-inc.com/catalog/product_info.php?products_id=941499
The programmer connects to the transmitters in the sensors, or other accessory – comes with instructions
Then, you must call tattletale with the serial number on the base unit to obtain the “house code” for that unit…
You then need to enter the house code into the programmer to program the accessory to match the base unit.