Man-trap: A physical access control system for preventing unauthorized access and separating security zones from non-security zones.

Master device: Among the devices that are connected through RS-485, the device that plays the role of a controller. It processes data by periodically monitoring the slave device. It is also called a host device.

Matching timeout: The time limit given to device matching or server matching. Matching fails if the matching does not get completed within the time limit.

Meal deduction: The act of excluding meal times when calculating the total number of daily working hours.

Message timeout: The duration of time a message is displayed when there is no user interaction.

Minutiae: The specific details in the ridges of a fingerprint used to recognize the fingerprint.

Model number: A generic number given to a device by the manufacturer in order to identify its type.

Monitoring: A surveillance activity for specific purposes. Monitoring access control and time and attendance management refers to checking access control events and user time and attendance events, as well as checking and controlling the status of devices, doors and zones in real time.

MSB (Most Significant Bit): The bit at the highest position of binary data (the left-most bit) or its content. It is the opposite of the Least Significant Bit (LSB).

MTU (Maximum Transmission Unit): The maximum amount of packets that can be transmitted through the network.

Multi-RFID technology: A technology that allows cards operating in different frequency bands, such as 125 kHz and 13.56 MHz, to be read from a single device.

Muster Zone: A zone designated for the gathering of members in case of an emergency such as a fire. This is used to monitor the number and roster of personnel in a certain zone, and to notify administrators via an alarm or alert if a user has remained in a particular zone for a certain period of time.