RS232, RS422 and RS485 are the recommended standards for digital communication. They serve as communication interface between computers, CCTV cameras, DVR/NVR, keyboards and other peripherals. They are called as an serial communication interface.

RS232 - In telecommunications, RS-232 is a standard for serial communication transmission of data. It formally defines the signals connecting between a DTE (data terminal equipment) such as a computer terminal, and a DCE (data circuit-terminating equipment or data communication equipment), such as a modem.It is a 3 wire unblanced line and used for data transmission over short distances

RS422 - This is an advanced format of digital communication with a 4 wire balanced. It cancels noise and carries messages over up to 1200m with multi-drop data transmission at up to 10 receivers. It is used in matrix switcher networks such that data is transmitted using one pair and another pair is used for data reception.

RS485 - A half duplex 2 wire balanced line that provides a much advanced format of data transmission in comparison to RS232. It is also superior to RS422 indicated by the number of receivers it can support with multi-drop data transmission increased upto 32 receivers. Used in remote control like PTZ cameras.