noun
modem
Technical computing term for a device that modulates and demodulates signals for data transmission.
インターネットに接続するには変復調装置が必要です。
A modem is needed to connect to the internet.
モデム is the common loanword for modem in everyday use; 変復調装置 is a formal technical term used mainly in engineering contexts.
Compound of 変調 (modulation), 復調 (demodulation), and 装置 (device).