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 ...

/ 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, 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 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 in

, 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