Broadband is a general term for high-speed, high-capacity internet. Speed thresholds vary by country; Japan generally considers 1Mbps+ always-on connections as broadband. ADSL, fiber optic, cable TV (CATV), and mobile broadband (4G/5G) qualify.
Japan's broadband adoption accelerated with the 2001 "e-Japan Strategy" targeting world-leading IT status by 2005. Yahoo! BB's ADSL price disruption followed by nationwide fiber deployment brought household broadband penetration to about 95% by 2024.
Broadband fundamentally changed telephony. High-speed lines enabled practical VoIP, video calls, cloud PBX, and telework. Traditional voice-only PSTN gave way to IP networks integrating voice, video, and data.
The digital divide between urban and rural areas remains a challenge. Satellite internet (Starlink) and mobile networks serve areas without fiber. See VoIP basics for broadband-telephony relationships.