In telecommunication, a public land mobile network (PLMN) is a combination of wireless communication services offered by a specific operator in a specific country.3GPP TS 21.905 https://www.etsi.org/deliver/etsi_tr/121900_121999/121905/15.00.00_60/tr_121905v150000p.pdf A PLMN typically consists of several cellular technologies like

GSM The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such as ...

/ 2G,

UMTS The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...

/ 3G, LTE/ 4G, offered by a single operator within a given country, often referred to as a

cellular network A cellular network or mobile network is a communication network where the link to and from end nodes is wireless. The network is distributed over land areas called "cells", each served by at least one fixed-location transceiver (typically thre ...

PLMN code

A PLMN is identified by a globally unique PLMN code, which consists of a MCC (Mobile Country Code) and MNC (Mobile Network Code). Hence, it is a five- to six-digit number identifying a country, and a mobile network operator in that country, usually represented in the form 001-01 or 001–001. A PLMN is part of a: * Location Area Identity (LAI) (PLMN and Location Area Code) * Cell Global Identity (CGI) (LAI and Cell Identifier) * IMSI (see

PLMN code and IMSI In telecommunication, a public land mobile network (PLMN) is a combination of wireless communication services offered by a specific operator in a specific country.3GPP TS 21.905 https://www.etsi.org/deliver/etsi_tr/121900_121999/121905/15.00.00_6 ...

)

Leading zeros in PLMN codes

Note that an MNC can be of two-digit form and three-digit form with leading zeros, so that 01 and 001 are actually two distinct MNCs. Hence the PLMNs 001-02 and 001-002 would be in the same country, but belong to two completely distinct operators (02 and 002). From PLMN assignments, it is apparent that such dualities of two-digit and three-digit MNCs with the same number value are avoided (see the list of mobile country codes and mobile network codes). An example for an actual three-digit/two-digit MNC with leading zeros is in Bermuda MCC, 350-007 and 350-00, 350-01.

PLMN code and IMSI

The IMSI, which identifies a SIM or USIM for one subscriber, typically starts with the PLMN code. For example, an IMSI belonging to the PLMN 262-33 would look like 262330000000001. Mobile phones use this to detect

roaming Roaming is a wireless telecommunication term typically used with mobile devices, such as mobile phones. It refers to a mobile phone being used outside the range of its native network and connecting to another available cell network. Technical ...

, so that a mobile phone subscribed on a network with a PLMN code that mismatches the start of the USIM's IMSI will typically display an "R" on the icon that indicates connection strength.

PLMN services

A PLMN typically offers the following services to a mobile subscriber: * Emergency calls to local Fire/Ambulance/Police stations. * Voice calls to/from any other PLMN ("cellular network") or

PSTN The public switched telephone network (PSTN) provides infrastructure and services for public telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local teleph ...

landline A landline (land line, land-line, main line, home phone, fixed-line, and wireline) is a telephone connection that uses metal wires or optical fiber telephone line for transmission, as distinguished from a mobile cellular network, which uses ...

VoIP Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...

). *

Short message service Short Message/Messaging Service, commonly abbreviated as SMS, is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile devices exchange short text ...

(SMS) services to/from any other PLMN or SIP service (the original form of

texting Text messaging, or texting, is the act of composing and sending electronic messages, typically consisting of alphabetic and numeric characters, between two or more users of mobile devices, desktops/laptops, or another type of compatible compute ...

on a mobile phone, now often replaced by

Messaging apps Instant messaging (IM) technology is a type of online chat allowing real-time text transmission over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and trigge ...

). *

Multimedia Messaging Service Multimedia Messaging Service (MMS) is a standard way to send messages that include multimedia content to and from a mobile phone over a cellular network. Users and providers may refer to such a message as a PXT, a picture message, or a multimedia ...

(MMS) services to/from any other PLMN or SIP service. *

Unstructured Supplementary Service Data Unstructured Supplementary Service Data (USSD), sometimes referred to as "quick codes" or "feature codes", is a communications protocol used by GSM cellular telephones to communicate with the mobile network operator's computers. USSD can be used ...

(USSD) for operator specific interactions (e.g. dialing "*#100#" to indicate the current balance). * Internet data connectivity for arbitrary services, e.g. via

GPRS General Packet Radio Service (GPRS) is a packet oriented mobile data standard on the 2G and 3G cellular communication network's global system for mobile communications (GSM). GPRS was established by European Telecommunications Standards Insti ...

, IuPS in

, or LTE. The availability, quality and bandwidth of these services strongly depends on the particular technology used to implement a PLMN.

References

{{Mobile telecommunications standards Mobile technology