Open: A state in which no current flows because a wire has been broken, causing the circuit to open.

Optical fingerprint sensor: A sensor that extract fingerprint information using light.

OSDP(Open Supervised Device Protocol): The standard RS-485 protocol developed by enhancing the Wiegand interface, through which only unidirectional communication from a reader to a controller was possible. This protocol enables processing of large amounts of data in a bidirectional reader-controller communication environment, as well as transmitting biometric data. Supporting this protocol also enables connectivity between third-party devices, so you can simply replace an existing system's items as necessary.

Output relays: An electronically controlled device that opens/closes electrical contacts in order to affect other devices.

Overtime: The time worked that is more than the daily working hours set by the Labor Standards Act or the company regulations. Overtime may include early work, extra work, holiday work, etc.