noun
access line
A telecommunications line connecting a user to a network or service provider; used in computing and networking contexts.
新しいアクセス回線を敷設するには許可が必要だ。
Permission is required to install a new access line.
回線 is a general term for a line or circuit, while アクセス回線 specifically refers to the line used for access, often in a network context.
Compound of アクセス (access) and 回線 (line/circuit). The exact historical derivation is uncertain, but it is a straightforward technical term.