Wiktionary
multiline
a. Consisting of multiple lines.
Usage examples of "multiline".
His desk looked like a command console, equipped with a standard multiline telephone, a STU-III encrypted telephone, and the preaddressed telephone system that networked all the other executive assistants on both the Navy headquarters staff and also in the office of the Chairman of the Joint Chiefs of Staff, who happened to be a navy admiral.
But it was comfortable enough, with a spacious work area, multiline phone, cable television, broadband Internet connection and a small, round conference table and four maroon leather chairs.