{{Short description|Telecommunications technology}} {{EngvarB|date=June 2023}} {{refimprove|date=October 2025}} A '''trunk prefix''' is a digit sequence to be dialed before a telephone number to initiate a telephone call for the purpose of selecting an appropriate [[telecommunications]] circuit by which the call is to be routed.<ref>{{Cite web |date=December 15, 2011 |title=DIALLING PROCEDURES (INTERNATIONAL PREFIX, NATIONAL (TRUNK) PREFIX AND NATIONAL (SIGNIFICANT) NUMBER) (IN ACCORDANCE WITH ITU-T RECOMMENDATION E.164 (11/2010)) |url=https://www.itu.int/dms_pub/itu-t/opb/sp/t-sp-e.164c-2011-pdf-e.pdf |access-date=October 16, 2025 |website=INTERNATIONAL TELECOMMUNICATION UNION}}</ref>
==Methodology== Telecommunication networks evolved from small, locally designed and managed networks within a city, region, state, province, etc. and grew by geographic expansion and the desire to communicate across the boundaries of such networks. For this purpose special trunks became available by which calls are routed for interconnection of different networks. The [[telephone numbering plan]]s were typically incompatible with those in other networks. Telephone companies enabled the routing via external trunks to other networks by requiring operators or subscribers to dial special prefix sequences prior to dialing the destination telephone number.
Before the implementation of [[direct distance dialing]] (DDD) in the United States, operators used routing codes to select specific trunks to the next intermediate destination, or, in [[Operator Toll Dialing]], an [[area code]] to forward the call to a remote [[numbering plan area]] toll switch. In Direct Distance Dialing the newest local (Class 5) switching systems did not require special prefixes in addition to the area code, but older systems were retrofitted with equipment that enabled a toll trunk by dialing a special prefix sequence.
Today, making a domestic (national) telephone call usually requires the dialing of a single or two-digit national trunk prefix preceding any [[area code]]s and the destination subscriber number. In most countries, the trunk prefix is 0.
For international telephone calls the caller must dial an [[List of international call prefixes|international trunk prefix]], followed by the destination's [[telephone country code|country code]]. Many mobile telephone systems also permit dialing the character ''+'' in place of the International trunk prefix to automatically substitute the appropriate code for the origination country.
For displaying an international telephone number in directories, [[business card]]s, or stationery, a telephone number is represented by prefixing it with a plus sign and the country code, without any local trunk prefixes.
== Countries using national trunk prefixes ==
=== Countries that use 0 as national trunk prefix ===
==== Africa ====
{{div col|colwidth=12em}} * [[Telephone numbers in Egypt|Egypt]] * [[Telephone numbers in Morocco|Morocco]] * [[Telephone numbers in Kenya|Kenya]] * [[Telephone numbers in South Africa|South Africa]] * [[Telephone numbers in Sudan|Sudan]] * [[Telephone numbers in Tanzania|Tanzania]] * [[Telephone numbers in Rwanda|Rwanda]] * [[Telephone numbers in Nigeria|Nigeria]] * [[Telephone numbers in Libya|Libya]] {{div col end}} *[[Telephone numbers in Angola |Angola]]
==== South America ====
{{div col|colwidth=12em}} * [[Telephone numbers in Argentina|Argentina]] * [[Telephone numbers in Brazil|Brazil]] * [[Telephone numbers in Paraguay|Paraguay]] * [[Telephone numbers in Peru|Peru]] * [[Telephone numbers in Venezuela|Venezuela]] {{div col end}}
==== Asia ====
{{div col|colwidth=12em}} * [[Telephone numbers in Afghanistan|Afghanistan]] * [[Telephone numbers in Azerbaijan|Azerbaijan]] * [[Telephone numbers in Bangladesh|Bangladesh]] * [[Telephone numbers in Cambodia|Cambodia]] * [[Telephone numbers in China|China]] (landlines only) * [[Telephone numbers in India|India]] (landlines only) * [[Telephone numbers in Indonesia|Indonesia]] * [[Telephone numbers in Iran|Iran]] * [[Telephone numbers in Israel|Israel]] * [[Telephone numbers in Japan|Japan]] * [[Telephone numbers in Jordan|Jordan]] * [[Telephone numbers in Laos|Laos]] * [[Telephone numbers in Malaysia|Malaysia]] * [[Telephone numbers in Myanmar|Myanmar]] * [[Telephone numbers in North Korea|North Korea]] * [[Telephone numbers in Nepal|Nepal]] * [[Telephone numbers in Pakistan|Pakistan]] * [[Telephone numbers in the Philippines|Philippines]] * [[Telephone numbers in Saudi Arabia|Saudi Arabia]] * [[Telephone numbers in South Korea|South Korea]] * [[Telephone numbers in Sri Lanka|Sri Lanka]] * [[Telephone numbers in Taiwan|Taiwan]] * [[Telephone numbers in Thailand|Thailand]] * [[Telephone numbers in Uzbekistan|Uzbekistan]] * [[Telephone numbers in Vietnam|Vietnam]] * [[Telephone numbers in the United Arab Emirates|United Arab Emirates]] {{div col end}}
==== Europe ====
{{div col|colwidth=12em}} * [[Telephone numbers in Albania|Albania]] * [[Telephone numbers in Austria|Austria]] * [[Telephone numbers in Belgium|Belgium]] * [[Telephone numbers in Bosnia and Herzegovina|Bosnia and Herzegovina]] * [[Telephone numbers in Bulgaria|Bulgaria]] * [[Telephone numbers in Croatia|Croatia]] * [[Telephone numbers in Finland|Finland]] * [[Telephone numbers in France|France]] * [[Telephone numbers in Georgia (country)|Georgia]] * [[Telephone numbers in Germany|Germany]] * [[Telephone numbers in the Republic of Ireland|Ireland]] * [[Telephone numbers in Lithuania|Lithuania]] * [[Telephone numbers in Moldova|Moldova]] * [[Telephone numbers in Montenegro|Montenegro]] * [[Telephone numbers in the Netherlands|Netherlands]] * [[Telephone numbers in North Macedonia|North Macedonia]] * [[Telephone numbers in Romania|Romania]] * [[Telephone numbers in Serbia|Serbia]] * [[Telephone numbers in Slovakia|Slovakia]] * [[Telephone numbers in Slovenia|Slovenia]] * [[Telephone numbers in Sweden|Sweden]] * [[Telephone numbers in Switzerland|Switzerland]] * [[Telephone numbers in Turkey|Turkey]] * [[Telephone numbers in Ukraine|Ukraine]] * [[Telephone numbers in the United Kingdom|United Kingdom]] {{div col end}}
==== Oceania ====
{{div col|colwidth=12em}} * [[Telephone numbers in Australia|Australia]] * [[Telephone numbers in New Zealand|New Zealand]] {{div col end}}
=== Countries that use 8 as national trunk prefix ===
{{div col|colwidth=22em}} * [[Telephone numbers in Belarus|Belarus]] * [[Telephone numbers in Kazakhstan|Kazakhstan]] * [[Telephone numbers in Russia|Russia]] (change to 0 planned) * [[Telephone numbers in Turkmenistan|Turkmenistan]] {{div col end}}
=== Countries that use other trunk prefixes === The number next to a country denotes its national trunk prefix.
{{div col|colwidth=22em}} * [[Telephone numbers in Mexico|Mexico]] – 01 * [[Telephone numbers in Mongolia|Mongolia]] – 01 or 02 * [[Telephone numbers in Hungary|Hungary]] – 06 * [[North American Numbering Plan]] countries – 1 {{div col end}}
== Countries that no longer use a national trunk prefix ==
{{div col|colwidth=22em}} * [[Telephone numbers in Bolivia|Bolivia]] * [[Telephone numbers in Chile|Chile]] * [[Telephone numbers in Cyprus|Cyprus]] * [[Telephone numbers in Czech Republic|Czech Republic]] * [[Telephone numbers in Denmark|Denmark]] * [[Telephone numbers in Estonia|Estonia]] * [[Telephone numbers in Greece|Greece]] — the prefix 0 was replaced by 2 for landlines and 6 for mobile phone numbers, which are now part of the number * [[Telephone numbers in Italy|Italy]] — the leading 0 is dialed both within and from outside Italy, because 0 is now part of the number and not the trunk code * [[Telephone numbers in Latvia|Latvia]] * [[Telephone numbers in Luxembourg|Luxembourg]] * [[Telephone numbers in Malta|Malta]] * [[Telephone numbers in Monaco|Monaco]] * [[Telephone numbers in Nepal|Nepal]] * [[Telephone numbers in Norway|Norway]] * [[Telephone numbers in Oman|Oman]] * [[Telephone numbers in Poland|Poland]] * [[Telephone numbers in Portugal|Portugal]] * [[Telephone numbers in San Marino|San Marino]] — the leading 0 is dialed both within and from outside Italy, because 0 is now part of the number and not the trunk code * [[Telephone numbers in Spain|Spain]] * [[Telephone numbers in Uruguay|Uruguay]] * [[Telephone numbers in Vatican City|Vatican City]] — the leading 0 is dialed both within and from outside Italy, because 0 is now part of the number and not the trunk code * [[Telephone numbers in Singapore|Singapore]] {{div col end}}
== See also == * [[Subscriber trunk dialling]]
== References == {{Reflist}}
== External links == *{{usurped|1=[https://web.archive.org/web/20021211223519/http://www.wtng.info/wtng-glo.html Glossary]}} — World Telephone Numbering Guide
{{DEFAULTSORT:Trunk Prefix}} [[Category:Telephone numbers]]