PHS (Personal Handy-phone System) was a lightweight mobile phone system developed in Japan. Using numbers starting with 070, it launched in 1995 and gained popularity primarily among individual consumers and healthcare facilities. At its peak in 1997, it reached approximately 7 million subscriptions and was affectionately known as "Picchi" (ピッチ).
PHS had several technical advantages over mobile phones. Call quality was superior (32kbps ADPCM codec, clearer audio than contemporary mobile phones), and its low radio output (about 10mW, roughly 1/200th of a mobile phone) minimized interference with medical equipment, making it ideal for hospital use. Base station (cell station) installation costs were about one-tenth of mobile base stations, and its microcell architecture (small cells with a radius of 100-500m) achieved high-density area coverage. Pricing was also cheaper than mobile phones, earning support from students and young adults.
The decline of PHS paralleled the increasing speed and decreasing cost of mobile phones. As 3G spread, mobile call quality caught up with PHS, and the introduction of flat-rate packet plans eliminated PHS's pricing advantage. Consumer services ended at the end of January 2021, after the shutdown originally planned for July 2020 was postponed due to the COVID-19 pandemic. The corporate telemetering (automated meter-reading) service ended at the end of March 2023, and with that every PHS service had shut down. The technical lineage did not end there: sXGP (shared eXtended Global Platform), a self-managed system in the 1.9 GHz band, was standardized as the successor to the on-premises PHS used for internal phone systems in hospitals and factories.
The 070 number block formerly used by PHS has been repurposed for mobile phone numbers since 2013 as a countermeasure against number exhaustion. Since PHS services shut down, numbers beginning with 070 are assigned as mobile phone numbers, so a 070 number tells you nothing about whether a line is PHS. See Differences Between 090/080/070 Numbers for details on number blocks and History of Phone Number Digit Lengths for the evolution of telecommunications technology.