Which of the following protocols was MOST likely used on this cable?

An administrator notices an unused cable behind a cabinet that is terminated with a DB-9 connector.

Which of the following protocols was MOST likely used on this cable?
A . RS-232
B . 802.3
C . ATM
D . Tokenring

View Answer

Answer: A

Explanation:

A DB-9 connector is used on serial cables. Serial cables use the RS-232 protocol which defines the functions of the 9 pins in a DB-9 connector. The RS-232 standard was around long before computers. It’s rare to see a new computer nowadays with a serial port but they were commonly used for connecting external analog modems, keyboards and mice to computers.