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Denwa

Modem

A modem (Modulator-Demodulator) converts digital data to analog signals (modulation) and back (demodulation). Developed to transmit computer data over analog telephone lines, it was essential in the internet's early days.

1990s dial-up connections used modems to access the internet via phone lines. The distinctive "screech" sound during connection was modems negotiating (handshaking) communication protocols. Maximum speed was 56kbps - about 1/18,000th of today's fiber optic 1Gbps.

Dial-up occupied the phone line, preventing calls during internet use. "Hang up the internet!" was a common 1990s household refrain. ADSL enabled simultaneous phone and internet use.

The term "modem" persists but refers to different devices: fiber ONUs and cable modems are broadly called modems. See telephone evolution for internet connection technology history.

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Related Terms

Telephone Line

A communication circuit for transmitting voice calls, including analog, ISDN, fiber optic, and mobile network types.

Asymmetric Digital Subscriber Line

High-speed internet technology using existing copper telephone lines, discontinued in 2024 as fiber optic lines became dominant.

Fiber Optic Line

A high-speed communication line using optical fiber, used for Hikari Denwa phone service and internet connectivity.

Broadband

A general term for high-speed, high-capacity internet connections including ADSL, fiber optic, and cable TV lines.

Analog Line

A traditional phone line that converts voice signals directly into electrical signals for transmission.

ISDN

A digital telephone line service. NTT's INS Net is the representative example.

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