NC (Normally Closed): An action where the relay remains closed in normal status but opens when the device operates. The current flows through the connected circuit because the relay remained closed earlier.

NFC(Near Field Communication): An RFID technology applied to mobile terminals to enable bidirectional transmission/reception of data at close range. With the rise in the smartphone penetration rate, this technology is increasingly used in various fields such as finance and communications, and it is also applied in access control in the form of mobile ID cards.

NO (Normally Open): An action where the relay remains open in normal status but closes when the device operates. The current does not flow through the circuit because the relay remained open earlier.

NVR(Network Video Record): A function that records and monitors videos of access points using cameras or video devices installed on the network, and manages events that occur.

Noise: The electrical signals that obscure or make it difficult to identify signals.