Which of the following is NOT a type of telephone system used on an airfield?

The correct answer indicates that a cellular system is not typically categorized as a type of telephone system used on an airfield. On airfields, communication is crucial for safety and operational efficiency, and the systems in use are often tailored to those specific needs.

The BT system, often referring to British Telecommunications, is a recognized standard for telephone services and infrastructure, including options suited for airfield communications. The Defence Fixed Telecoms System is designed to meet military requirements and is integral to communications for operations, ensuring secure and reliable connections. Landlines are the traditional method of communication, widely used in various locations, including airfields, providing straightforward reliability.

In contrast, while cellular systems are prevalent in many areas for personal communication, they are not typically the primary choice for airfield operations due to factors like reliability, security, and susceptibility to interference, making them less suitable for critical operational communication.