To ensure proper functionality, specially to avoid interference of the analogue line of 2N EasyGate/SmartGate, proper grounding is needed. You can complete it through a left pin in the SMS input (Pic. 1) for new models of 2N EasyGate PRO and 2N SmartGate UMTS.

In case of an old version 2N EasyGate/SmartGate use right pin in the SMS input!

Pic. 1