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A Glossary of Terms to Know Before Deciding on a Telecom

Top10.com Staff
glossary of terms
If you’re sizing up telecom providers to support your cellular needs, then you may be having a hard time deciphering the alphabet soup. Don’t know your MVNO from your roaming? (Yes, those are totally different things.) Follow our glossary to get up to speed on some of the most common terms in this area.

4G (LTE)

A member of the GSM network family, 4G (LTE) is today’s standard for fast network connectivity.  4G no longer represents the latest and greatest network speed out there — that would be 5G — but it still provides a reliably fast connection speed. Typically, maximum download speeds are about 100 Mbps, although theoretically the speeds could reach 300 Mbps.


5G is the next evolution in terms of GSM-based cellular networks. 5G can comfortably deliver speeds in excess of 100 Mbps. The fastest 5G speed was achieved on an AT&T network and measured more than 1 Gbit/s.


There are two main operating systems (OSes) used by mobile devices: iOS and Android. Many telecom providers will insist that customers buy one of their own phones and Androids are popular options. There are many variants of Android device on the market supported by many manufacturers. Compared to iOS, Android devices tend to be easier to customize. 


Bandwidth refers to the maximum rate of data transfer between two points. In the world of cellular telecom providers this effectively refers to the data speed that the network can deliver. This isn’t the same thing as data usage which refers to the actual quantity of data transferred. If your telecom provider has a data cap then they’re probably referring to a total data transfer limit. Although bandwidth caps are also possible.

Base Station

In cellular connectivity, a base station is a cellular tower that is responsible for transmitting the network over the RF radio bands. These are key parts of the network infrastructure. If a telecom tells you that they are installing base stations in your zip code, then it likely means that your network quality and coverage is going to improve. 


Bring Your Own Device (BYOD) is a billing and operational model whereby cellular providers allow customers to “bring” their own devices to the network. For BYOD, you’ll need to make sure that your phone is unlocked. Once your handset is in this condition, depending upon whether it’s a CDMA or GSM-based device, it can either be remotely activated or activated after inserting the carrier-provided SIM.

Call Over WiFi 

Also known as WiFi calling, Call Over Wifi means that your carrier will route a call over a WiFi network rather than through cellular connectivity. If you place a call in this manner, the phone will automatically select and connect through the best network. Relative to cellular, this results in improved call performance.

Cellular Internet

Cellular internet is essentially internet connectivity that is transmitted wirelessly from a telecom’s infrastructure to a device. When you turn on data on your handset, you are actually turning on the radio receiver that picks up this network. Think about it like a really wide WiFi network that reaches to your phone.


Code Division Multiple Access (CDMA) is a type of cellular network connectivity whereby connecting devices don’t need to have an operator-issued SIM card in order to connect to the network. Instead the device itself (the cellular handset) is authenticated with the network. Certain mobile operators, and MVNOs, support CDMA, whereas others support GSM.

Dual SIM

Dual SIM is a type of handset that, as the name suggests, can support two SIM cards simultaneously. There are also handsets on the market with three and more SIMs. Certain telecoms will cell handsets with this capability.

Fair Use Limit

There’s no such thing as a free lunch and in the world of cellular connectivity there’s often no such thing as truly unlimited data. Instead, study the fine print and you’ll often find that providers enforce fair use limits which are caps on the amount of bandwidth that subscribers can access even on unlimited plans.


Global System for Mobiles (GSM) connectivity involves using an older radio system that requires a SIM card to be in the phone to connect to the operator’s network. Compare with: CDMA.


iOS is a mobile operating system that is maintained by the Apple company. It is the OS that is used in the iPhone family of devices. Many telecoms make these devices available in rental and payback deals. 


This acronym stands for megabits per second. Mbps is a measure of the download speed of a network (it can also measure upload speed but subscribers typically aren’t as concerned with this). The higher the number, the stronger the connection.


A mobile network operator (MNO) is a telecom that owns and operates its own infrastructure to support network connectivity.


A mobile virtual network operator (MVNO) is a telecom that doesn’t own its own infrastructure. Instead it resells bandwidth that it leases from an MNO.


Prepaid phone plans are plans that are paid in advance rather than through the usage and later issuing of bills. Compared with bill pay plans these connection plans are paid on debit rather than credit.

Pay As You Go

Pay as you go (PAYG) is essentially the same thing as prepaid. You pay for credit and then top up using vouchers as you consume bandwidth and other services.


Porting a number into a provider means moving it from another provider into the one you wish to connect to. This process can take a number of days but allows you to retain your old phone number.


Roaming refers to using your cellular connection plan while in another geography outside the territory covered by your phone plan (which is typically the country in which you reside). Roaming can be expensive so it’s important to learn about costs before using your headset overseas.

SIM Card

A Subscriber Identity Module (SIM) card is a type of identification module that’s placed into a cellphone to provide it with connectivity. The SIM card identifies your phone to the network operator and allows it to receive services.


A smartphone is a telephone that is equipped with the ability to receive mobile internet. A “dumbphone” is a phone without these capabilities. These days, dumb phones are far less common.


Short messaging service (SMS) is a protocol for relaying text based messages.


Throttling refers to a practice whereby the network operator artificially limits connection speeds in order to preserve bandwidth on the network. This can also happen when subscribers go past their data limit.

Unlocked phone

An unlocked phone is a device that isn’t tied to a specific network operator. Instead it can be used with any telecom that it can connect to through having the right kind of radio receiver. Typically when a network supports bring your own device you’ll have to unlock your device first. 


Voice over IP means using the internet to relay voice communications. If you’ve ever placed a Skype or WhatsApp call then you’ve used VoIP.

Top10.com Staff
Top10.com's editorial staff is a professional team of editors and writers with dozens of years of experience covering consumer, financial and business products and services.