2N Fixed line replacement with 2N SmartGate - Manual v1.1.2 - Manual (Page 72)

SIM Card PIN protection 4.5
72
Automatic PIN Entering
You need not enter the PIN upon power up if it is stored in 2N® SmartGate – it is
entered automatically. This function is useful in case of power failure; 2N®
SmartGate is operable in a short time after power recovery without any
intervention by the operating staff.
Caution!
 One PIN entering option is exhausted by the attempt to enter the PIN
automatically upon SIM card or PIN change. If wrong, the automatically
entered PIN is cleared from the internal memory to avoid another false
attempt upon next power on. There are still two manual PIN-entering
attempts after such unsuccessful automatic entering. To prevent the
unsuccessful automatic PIN entering, delete or program properly the 2N®
SmartGate PIN using the PCManager in the case of SIM card change.