What would you install if the manager wants a local connection as well as an outside line?

The most suitable choice for providing both a local connection and an outside line would be a Private Automatic Branch Exchange (PABX). A PABX system is designed to manage internal telephone lines while also connecting to external phone lines, facilitating communication both within a building and externally. This makes it an ideal solution for a scenario where a manager needs to maintain local calls among staff and have the capability to connect to outside lines for external communication.

Other options do not directly fulfill the requirement. An intercom system primarily facilitates internal communication and may not connect to the public telephone network. CATV, or community antenna television, focuses on delivering television programming and doesn't support telephone communication. CCTV refers to closed-circuit television systems for surveillance, which is unrelated to telephony functions. Thus, the use of a PABX is essential for achieving the required connectivity in this case.