noun
trunk coupling unit; trunk connecting unit; TCU
Computing term for a device that connects trunk lines in a network or telephone system.
幹線結合器は、ネットワークの幹線同士を接続する装置です。
A trunk coupling unit is a device that connects trunk lines in a network.
Compound of 幹線 (trunk line) + 結合 (coupling) + 器 (device).