The Apache 700XR is a GSM acces control unit
The system is completely safe, acces will only be granted to registered visitors. When using, there is no standard code, because your phone number is the code. This leads to incapability of granting acces to third. It is very easy to add or remove a user. One simple text message is enough.
The Apache 700XR has space for 2000 different phone numbers including 400 "special" numbers for acces within time tables.