View source for Personal Handy-phone System

{{Short description|Discontinued cellular telephone network standard}}
{{redirect|PIAFS|the singular|piaf (disambiguation)}}
The '''Personal Handy-phone System''' ('''PHS'''), also known as the '''Personal Communication Telephone''' ('''PCT''') in Thailand, and the '''Personal Access System''' ('''PAS''') and commercially branded as '''''Xiaolingtong''''' ({{zh|c=小灵通}}) in [[China]], was a [[mobile network]] system operating in the 1880–1930 [[MHz]] frequency band. In [[Japan]], it was introduced as a low-cost wireless service with smaller coverage areas than standard cellular networks. Its affordability made it popular in China, [[Taiwan]], and other parts of [[Asia]], as both the handsets and network infrastructure were relatively inexpensive to maintain.<ref>{{Cite news |date=2005-03-01 |title=NTT giving up on discount wireless |url=https://www.nytimes.com/2005/03/01/technology/ntt-giving-up-on-discount-wireless.html |access-date=2025-03-08 |work=The New York Times |language=en-US |issn=0362-4331}}</ref>

Developed in the 1990s, PHS used a [[microcell]] architecture with low-power base stations covering {{Convert|100 to 500|m}}. unlike conventional [[Cellular network|cellular networks]] that relied on large cell sites for extensive coverage, PHS’s design was better suited for dense urban environments and reduced infrastructure costs.

PHS was overtaken in the marketplace by [[GSM]] (3G) and [[UMTS]] (4G), with the last retail network decommissioned in 2021 and the last commercial network terminated in 2023.<ref name=last>https://japannews.yomiuri.co.jp/business/companies/20230402-101032/</ref>

== Outline ==

=== Technology ===
[[Image:Mobile phone PHS Japan 1997-2003.jpg|thumb| PHS Japan 1997–2003 ([[Willcom]], [[NTT DoCoMo]], [[ASTEL]])]]
PHS is essentially a [[cordless telephone]] like [[Digital Enhanced Cordless Telecommunications|DECT]], with the capability to [[handoff|handover]] from one [[cellular network|cell]] to another. PHS cells are small, with transmission power of [[base station]] a maximum of 500&nbsp;mW and range typically measures in tens or at most hundreds of metres (some can range up to about 2 kilometres in line-of-sight), contrary to the multi-kilometre ranges of [[CDMA]] and [[GSM]]. This makes PHS suitable for dense urban areas, but impractical for rural areas, and the small cell size also makes it difficult if not impossible to make calls from rapidly moving vehicles.

PHS uses [[Time-division multiple access|TDMA]]/[[Time-division duplex|TDD]] for its radio [[channel access method]], and 32&nbsp;kbit/s [[ADPCM]] for its voice [[codec]]. Modern PHS phone can also support many [[value-added service]]s such as high speed wireless [[data]]/[[Internet]] connection (64&nbsp;kbit/s and higher), [[World Wide Web|WWW]] access, [[e-mail]]ing, and text messaging.

PHS technology is also a popular option for providing a [[wireless local loop]], where it is used for bridging the "[[Last mile (telecommunications)|last mile]]" gap between the [[plain old telephone service|POTS]] network and the subscriber's home. It was developed under the concept of providing a wireless [[front and back ends|front-end]] of an [[Integrated Services Digital Network|ISDN]] network. Thus a PHS base station is compatible with ISDN and is often connected directly to ISDN [[telephone exchange]] equipment e.g. a digital switch.

In spite of its low-cost [[base station]], [[Microcell|micro-cellular]] system and "Dynamic Cell Assignment" system, PHS offers higher number-of-digits frequency use efficiency with lower cost (throughput per area basis), compared with typical [[IMT-2000|3G]] [[cellular telephone]] systems. It enables flat-rate wireless service such as [[AIR-EDGE]], throughout Japan.

The speed of an AIR-EDGE data connection is accelerated by combining lines, each of which basically is 32&nbsp;kbit/s. The first version of AIR-EDGE, introduced in 2001, provided 32&nbsp;kbit/s service. In 2002, 128&nbsp;kbit/s service (AIR-EDGE 4×) started and in 2005, 256&nbsp;kbit/s (8×) service started. In 2006, the speed of each line was also upgraded to 1.6 times with the introduction of "W-OAM" technology. The speed of AIR-EDGE 8× is up to 402&nbsp;kbit/s with the latest "W-OAM" capable instrument.

In April 2007, "W-OAM typeG" was introduced allowing data speeds of 512&nbsp;kbit/s for AIR-EDGE 8x users. Furthermore, the "W-OAM typeG" 8× service was planned to be upgraded to a maximum throughput of 800&nbsp;kbit/s, when the upgrading for access points (mainly switching lines from ISDN to [[Optical fiber|fibre optic]]) in its system are completed. Thus it was expected to exceed the speeds of popular [[W-CDMA]] 3G service like [[NTT DoCoMo]]'s [[FOMA]] in Japan.

=== Implementation ===
[[File:PHS ASTEL 06c2774as.jpg|thumb|ASTEL-brand PHS [[Base station]] in Tokyo, Japan]]
Developed by [[Nippon Telegraph and Telephone|NTT Laboratory]] in Japan in 1989 and far simpler to implement and deploy than competing systems like [[Personal Digital Cellular|PDC]] or [[GSM]], the commercial services were started by three PHS operators (NTT-Personal, DDI-Pocket, and ASTEL) in Japan in 1995, forming the PIAF ([[PHS Internet Access Forum]]). However, the service was pejoratively dubbed as the "poor man's cellular", due to its limited range and roaming abilities. NTT DoCoMo, which absorbed NTT Personal, and ASTEL terminated the PHS service in January 2008.

In Thailand, TelecomAsia (now [[True Corporation]]) integrated the PHS system with [[Intelligent Network]] and marketed the service as Personal Communication Telephone (PCT).<ref>{{cite book |last1=Calvert |first1=John |title=Network Services: Thailand |date=16 May 2003 |publisher=Gartner |url=https://www.bus.umich.edu/kresgepublic/journals/gartner/research/114900/114968/114968.html |access-date=17 February 2019 |archive-url=https://web.archive.org/web/20190217035709/https://www.bus.umich.edu/kresgepublic/journals/gartner/research/114900/114968/114968.html |archive-date=17 February 2019}}</ref> The integrated system was the world's first that allowed the [[fixed line]] telephone subscribers of the [[public switched telephone network]] to use PHS as a value added service with the same telephone number and shared the same voice mailbox.<ref name="form 56-1">{{cite book |title=Report Form 56-1 For the Year 2001 TelecomAsia Corporation Public Company Limited |date=2001 |pages=15, 22 |url=http://investor.truecorp.co.th/misc/FORM561/20020329-TRUE-Form561-2001-EN.pdf |access-date=31 October 2021 |archive-url=https://web.archive.org/web/20211031223523/http://investor.truecorp.co.th/misc/FORM561/20020329-TRUE-Form561-2001-EN.pdf |archive-date=31 October 2021}}</ref><ref>{{cite news |title=Excel switches to be deployed in major telecom installation in Thailand. |url=https://www.thefreelibrary.com/Excel+switches+to+be+deployed+in+major+telecom+installation+in+...-a019461161 |access-date=19 February 2019 |work=Excel, Inc. Press Release |date=30 May 1997 |archive-url=https://web.archive.org/web/20190220002859/https://www.thefreelibrary.com/Excel+switches+to+be+deployed+in+major+telecom+installation+in+...-a019461161 |archive-date=20 February 2019}}</ref> The PCT service was commercially launched in November 1999 with the peak of 670,000 subscribers in 2001. However, the number of subscribers had declined to 470,000 in 2005 before the breakeven in 2006 after six years of heavy investment up to 15 billion THB. With the popularity of other cellular phone services, the company shifted the focus of the PCT to a niche market segment of youths ages 10-18.<ref>{{cite news |title=True's WE PCT to finally break even |url=https://www.commsupdate.com/articles/2006/03/23/trues-we-pct-to-finally-break-even/ |access-date=17 February 2019 |work=TeleGeography |date=23 Mar 2006}}</ref>

[[Wireless local loop]] (WLL) systems based on PHS technology are in use in some of the above-mentioned countries. [[Willcom|WILLCOM]], formerly DDI-Pocket, introduced flat-rate [[wireless network]] and flat-rate calling in Japan, which reversed the local fate of PHS up to an extent. In China, there was an explosive expansion of subscribers until around 2005. In Chile, [[:es:Telefónica del Sur|Telefónica del Sur]] launched a PHS-based telephony service in some cities of the southern part of the country in March 2006. In Brazil, [[Suporte Tecnologia]] has a PHS-based telephony service in [[Betim]], state of Minas Gerais{{Update inline|date=October 2023}}, and [[Transit Telecom]] announced a rollout of a PHS network in 2007{{Update inline|date=October 2023}}.

[[China Telecom]] operated a PAS system in China, although technically it was not regarded as allowed to provide mobile services, because of some particularities of the Chinese governance. [[China Netcom]], the other fixed-line operator in China, also provides Xiaolingtong service. The system was a runaway hit, with over 90 million subscribers signed up {{As of|2007|lc=on}}; the largest equipment vendors were [[UTStarcom]] and [[ZTE]]. However, low priced mobile phones rapidly replaced PHS. The [[Ministry of Industry and Information Technology of the People's Republic of China]] issued notices on 13 February 2009 that both registration of new users and expansion of the network were to be discontinued, with the service to be ended by the end of 2011.<ref>[http://www.cn-c114.net/575/a387172.html MIIT Ceases PHS Registration, Network Expansion] {{Webarchive|url=https://web.archive.org/web/20150328014150/http://www.cn-c114.net/575/a387172.html |date=2015-03-28 }}.</ref>

A PHS global roaming service was available between Japan (WILLCOM), Taiwan, and Thailand.

== Commercial deployments ==

This is a list of commercial PHS deployments around the world, all of which are now defunct:<ref>{{cite web |url=http://www.phsmou.org/resources/PHSGuidebook_4th.pdf |title=PHS Guidebook (4th Edition) |publisher=PHS MoU Group |date=2008-09-29 |access-date=2016-01-29 |archive-url=https://web.archive.org/web/20160204190331/http://www.phsmou.org/resources/PHSGuidebook_4th.pdf |archive-date=2016-02-04 |url-status=dead }}</ref>

{| class="wikitable"
|-
! Country
! Operator
! [[Frequency|f]] (MHz)
! Launch date
! End of service
! Notes
|-
| {{flag|Japan}}
| [[NTT DoCoMo]]
| 1884,65–1919,45
| {{dts|Jul 1995}}
| {{dts|Jan 2008}}
| <ref name="PHS Frequency JP" /><ref>{{cite web |url=https://www.commsupdate.com/articles/2003/09/12/docomo-to-scale-back-phs-operations-and-focus-on-3g/ |title=DoCoMo to scale back PHS operations and focus on 3G |publisher=TeleGeography |date=2003-09-12 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2005/02/18/no-more-phs-for-docomo/ |title=No more PHS for DoCoMo |publisher=TeleGeography |date=2005-02-18 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2006/02/01/docomo-to-unveil-hsdpa-handsets-shut-down-phs-network-in-2007/ |title=DoCoMo to unveil HSDPA handsets; shut down PHS network in 2007 |publisher=TeleGeography |date=2006-02-01 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2007/04/30/docomo-to-shut-down-phs-services-next-year/ |title=DoCoMo to shut down PHS services next year |publisher=TeleGeography |date=2007-04-30 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2008/01/07/docomo-to-exit-phs-following-drop-in-subscribers/ |title=DoCoMo to exit PHS following drop in subscribers |publisher=TeleGeography |date=2008-01-07 |access-date=2016-01-29}}</ref>
|-
| {{flag|Japan}}
| [[SoftBank Mobile|Softbank]]<br/><small>(Y!mobile)</small>
| 1884,65 - 1919,45
| {{dts|Jul 1995}}
| {{dts|Jan 2021}} (retail)<br/>
{{dts|Apr 2023}} (commercial)<ref name=last/>
| <ref name="PHS Frequency JP">{{cite web|url=http://www.rft.jp/rft-english/Frequency.pdf |title=Japan permit Frequency and class of emissions |publisher=SGS RF Technologies |date=2015-10-22 |access-date=2016-01-29 |archive-url=https://web.archive.org/web/20160327142929/http://www.rft.jp/rft-english/Frequency.pdf |archive-date=27 March 2016}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2004/06/22/carlyle-and-kyocera-agree-deal-for-ddi-pocket/ |title=Carlyle and Kyocera agree deal for DDI Pocket |publisher=TeleGeography |date=2004-06-22 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2005/06/21/willcom-to-launch-high-speed-phs/ |title=Willcom to launch high speed PHS |publisher=TeleGeography |date=2005-06-21 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2006/07/19/adaptix-tests-japanese-phs-upgrade/ |title=Adaptix tests Japanese PHS upgrade |publisher=TeleGeography |date=2006-07-19 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2009/03/16/carlyle-to-increase-willcom-stake-paper-says/ |title=Carlyle to increase Willcom stake, paper says |publisher=TeleGeography |date=2009-03-16 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2009/11/27/softbank-named-as-possible-bidder-for-carlyles-struggling-willcom-unit/ |title=Softbank named as possible bidder for Carlyle's struggling Willcom unit |publisher=TeleGeography |date=2009-11-27 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2010/03/12/phs-provider-willcom-to-be-split-investors-to-provide-financial-aid/ |title=PHS provider Willcom to be split; investors to provide financial aid |publisher=TeleGeography |date=2010-03-12 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2010/10/15/softbank-to-buy-100-of-phs-operator-willcom/ |title=Softbank to buy 100% of PHS operator Willcom |publisher=TeleGeography |date=2010-10-15 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2014/06/02/eaccess-and-willcom-merge-under-the-ymobile-banner/ |title=eAccess and Willcom merge under the Ymobile banner |publisher=TeleGeography |date=2014-06-02 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2014/09/30/mnp-service-for-phs-subscribers-in-japan-from-1-october/ |title=MNP service for PHS subscribers in Japan from 1 October |publisher=TeleGeography |date=2014-09-30 |access-date=2016-01-29}}</ref><ref>{{cite web|url=https://www.commsupdate.com/articles/2018/04/20/softbank-announces-phs-switch-off-in-july-2020/ |title=SoftBank announces PHS switch-off in July 2020 |publisher=TeleGeography |date=2018-04-20 |access-date=2018-04-20}}</ref><br/>[[Willcom]] merged with [[eAccess]] into [[Ymobile|Y!mobile]] in 2014.<br/>Operated by Carlyle (Willcom) (2004–2010).<br/>Operated by [[KDDI]] (DDI Pocket) (1995–2004).<br/>{{mono|070}} prefix under the [[Telephone numbers in Japan|Japanese telephone numbering plan]].
|-
| {{flag|Hong Kong}}
|
| 1895–1906,1
| {{dts|1997}}
| {{dts|May 2016}}
| <ref>{{cite web |url=https://www.commsupdate.com/articles/2011/11/25/ofta-proposes-refarming-phs-1900mhz-frequencies-for-mobile-data-services/ |title=OFTA proposes refarming PHS 1900MHz frequencies for mobile data services |publisher=TeleGeography |date=2011-11-25 |access-date=2013-07-05}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2012/03/02/no-more-phs-services-concludes-ofta/ |title=No more PHS services, concludes OFTA |publisher=TeleGeography |date=2012-03-02 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2013/04/23/ofca-begins-phs-shut-down/ |title=OFCA begins PHS shut down |publisher=TeleGeography |date=2013-04-23 |access-date=2016-01-29}}</ref><ref>{{cite web |url=http://www.policytracker.com/headlines/end-of-phs-in-hong-kong |title=Hong Kong waves goodbye to PHS |publisher=PolicyTracker |date=2016-05-05 |access-date=2016-12-31 |archive-url=https://web.archive.org/web/20170101092651/http://www.policytracker.com/headlines/end-of-phs-in-hong-kong |archive-date=2017-01-01 |url-status=dead }}</ref>
|-
| {{flag|China}}
| [[China Unicom]]<br />[[China Telecom]]<br /><small>(Xiaolingtong)</small><br /><small>(Little Smart)</small>
| 1900–1920
| {{dts|1998}}
| {{dts|Sep 2013}}
| <ref>{{cite web |url=https://www.commsupdate.com/articles/2009/02/04/phs-networks-to-make-way-for-td-scdma/ |title=PHS networks to make way for TD-SCDMA |publisher=TeleGeography |date=2009-02-04 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2013/07/25/unicom-to-shut-down-phs-service/ |title=Unicom to shut down PHS service |publisher=TeleGeography |date=2013-07-25 |access-date=2016-01-29}}</ref>
|-
| {{flag|Thailand}}
| [[True Corporation]]<br />
| 1906,1 - 1918,1
| {{dts|Nov 1999}}
| {{dts|2013}}
| <ref>{{cite book |title=Other radio communication equipment permitted by NTC |date=January 2011 |publisher=Telecommunication Engineering and Technology Bureau |url=http://www.cerpass.com.tw/images/Thailand_Controlled%20product%20list.pdf |access-date=17 February 2019 |archive-url=https://web.archive.org/web/20190217142701/http://www.cerpass.com.tw/images/Thailand_Controlled%20product%20list.pdf |archive-date=17 February 2019}}</ref><ref>{{cite book |title=Thailand |publisher=ITU-D Study Groups |page=15 |url=https://www.itu.int/ITU-D/study_groups/SGP_2002-2006/JGRES09/THAILAND.PDF |access-date=17 February 2019}}</ref><ref name="form 56-1" /><br />Additional service for fixed-line subscribers.
|-
| {{flag|Taiwan}}
| [[First International Telecom|Fitel]]
| 1905–1915
| {{dts|May 2001}}
| {{dts|Mar 2015}}
| <ref name="PHS Frequency TW">{{cite web |url=http://spectrumfutures.org/wp-content/uploads/2015/04/Yu-Spectrum-Planning-Progress-in-Taiwan.pdf?1d1f06 |title=Spectrum Planning Progress in Taiwan |publisher=National Communications Commission (NCC) |date=2014-10-30 |access-date=2016-02-03}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2005/11/15/fitel-looking-to-boost-sales-of-dual-technology-phs-gsm-handsets/ |title=Fitel looking to boost sales of dual technology PHS-GSM handsets |publisher=TeleGeography |date=2005-11-15 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2013/02/11/fitel-planning-to-upgrade-phs-infrastructure/ |title=Fitel planning to upgrade PHS infrastructure |publisher=TeleGeography |date=2013-02-11 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2014/04/22/fitels-phs-coverage-shrinks-as-its-switches-off-base-stations-to-reduce-costs/ |title=Fitel's PHS coverage shrinks as its switches off base stations to reduce costs |publisher=TeleGeography |date=2014-04-22 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2015/01/05/bankrupt-fitel-facing-licence-cancellation-as-ncc-outlines-plans-to-reassign-numbers/ |title=Bankrupt Fitel facing licence cancellation as NCC outlines plans to reassign numbers |publisher=TeleGeography |date=2015-01-05 |access-date=2016-01-29}}</ref><ref>{{cite web |url=https://www.commsupdate.com/articles/2015/05/05/fitel-numbers-to-be-reassigned-to-existing-operators/ |title=Fitel numbers to be reassigned to existing operators |publisher=TeleGeography |date=2015-05-05 |access-date=2016-01-29}}</ref>
|-
| {{flag|Chile}}
| [[:es:Telefónica del Sur|Telefónica del Sur]]
| 1910–1930
| {{dts|Mar 2006}}
| {{dts|May 2011}}
| <ref>{{cite web |url=http://www.bnamericas.com/es/news/tic/Telsur_lanza_PHS_en_plataforma_de_UTStarcom |title=Telsur lanza PHS en plataforma de UTStarcom |publisher=Business News Americas |language=es |date=2006-03-23 |access-date=2017-04-16}}</ref><ref>{{cite web |url=http://www.emol.com/noticias/tecnologia/2008/11/08/329863/telefonica-del-sur-lanza-al-mercado-telefono-dual-unico-en-latinoamerica.html |title=Telefónica del Sur lanza al mercado teléfono dual único en Latinoamérica |publisher=El Mercurio |language=es |date=2008-11-08 |access-date=2017-04-16 |archive-url=https://web.archive.org/web/20170517051246/http://www.emol.com/noticias/tecnologia/2008/11/08/329863/telefonica-del-sur-lanza-al-mercado-telefono-dual-unico-en-latinoamerica.html |archive-date=17 May 2017}}</ref>
|}

==List of PHS-enabled CompactFlash cards==
{{Anchor|CompactFlash}}
[[File:DoCoMo Eggy.jpg|thumb|DoCoMo Eggy viewing "Personal Handy-Phone System" page on English Wikipedia with a P-in Comp@ct mobile data card.]]

PHS-enabled [[PCMCIA]]/[[CompactFlash]] cards include:

* [[TDK]] ''DF56CF''
*
* NTT DoCoMo ''P-in m@ster''
* NTT  ''P-in memory''
* [[DDI-Pocket|DDI]] ''AirH”Card petit'' [''RH2000'']
* DDI ''AirH”Card petit'' [''{{Interlanguage link multi|CFE-02|ja}}''
* DDI ''C@rdH”64 petit'' [''{{Interlanguage link multi|CFE-01|ja}}'']
* DDI ''C@rdH”64 petit'' [''CFE-01/TD'']

{{See also|Eye-Fi|Trek Flucard|PQI Air Card}}

==See also==
{{Portal|Telephones}}
*[[CT2]] – similar system in Europe, Canada and Hong Kong
*[[OpenBTS]] – low-cost GSM access

==References==
{{Reflist|30em}}

==External links==
{{commons|PHS}}
* [http://www.xgpforum.com/ PHS MoU Group (PHS MoU was dissolved and absorbed into a new organization "XGP Forum" in 2009.]
* [http://www.newsgd.com/business/bizevents/200305230014.htm Article on Xiaolingtong]
* [https://web.archive.org/web/20070113084359/http://www.phs.com.tw/en/index.asp PHS] in Taiwan
* [http://www.telsur.cl Telefonica del Sur] in Chile

{{Mobile telecommunications standards}}
{{Telecommunications}}

[[Category:Telecommunications-related introductions in 1995]]
[[Category:1995 establishments in Japan]]
[[Category:First generation mobile telecommunications]]
[[Category:Local loop]]
[[Category:Mobile telecommunications user equipment]]
[[Category:Japanese inventions]]