In the know: your broadband jargon buster

Do you know your ADSL from your FTTP, or what your router actually does? Do you know what bandwidth is, or what buffering means?

Broadband services are often described using a blizzard of acronyms and jargon. You don’t need to be an expert in connectivity to enjoy a great online experience, but knowing the basic terminology can be useful when you’re working out what kind of upgrade is best for you, or what’s going wrong with the broadband you already have.

In this jargon buster, we’ve distilled all that tech-speak down and defined the key terms that anyone with a broadband connection might find useful.

ADSL (ADSL2, ADSL2+)

ADSL, or Asymmetric Digital Subscriber Line, is an internet connection over an analogue line. It’s basically the technology that allows you to access the internet over the old copper “landline” network, and it’s the most basic broadband available today. ADSL is being phased out in 2027. ADSL2 and ADSL2+ are simply more advanced variants of the same technology.

Bandwidth

You’ll often hear internet performance described in terms of bandwidth, which is the amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in Mbps (megabits per second).

Bps

Bits per second, a measure of how fast data is transferred from one place to another.

Buffering

Buffering usually refers to the delay that happens when data is transferred between an internet-based service and your device, which you might experience as the dreaded spinning circle, also (unaffectionately) known as the wheel of doom. It commonly happens when streaming video or playing games, when the download speed of the data can’t keep up with the playback speed of the content. Moving your router, switching from a wireless to a wired connection and clearing cache can all help. Sometimes, solving chronic buffering requires a broadband upgrade.

Cloud

When internet services are described as “in the cloud”, it means data, applications, storage and more are accessed on demand via the internet from a shared central resource.

Download

The movement of packets of data from the internet to a user, usually expressed in Mbps. Broadband performance is often described in terms of download speeds, but upload speeds are also important.

Fibre

Internet connectivity that uses glass threads - bundled together into a fibre optic cable - to transmit data. Messages travel as light waves. Fibre is far faster and more reliable than copper alternatives.

FTTC

Fibre to the Cabinet (FTTC) is a part-fibre broadband technology. Information travels from the internet to a local exchange on fibre optic cables, before transferring to copper for the shorter journey to a user’s premises. The fibre part is lightning quick, the copper leg much slower, making FTTC faster than ADSL but slower than full fibre. A typical maximum FTTC download speed is around 76Mbps.

FTTP

Fibre to the Premises (FTTP), also known as full fibre, means data travels all the way from the internet to a user’s premises on fibre optic cables, making it the fastest connectivity available. A typical maximum FTTP download speed is currently around 900Mbps, but it can get considerably faster.

Gbps

Gigabits per second is a measure of bandwidth for fast digital services, such as top of the range FTTP. Slower connectivity will express speeds as Mbps.

ISDN

The Integrated Services Digital Network (ISDN) is a telecommunications network through which sound, images, and data can be transmitted as digitised signals. It’s outdated and, along with the Public Switched Telephone Network (PSTN), will finally be switched off in January 2027.

ISP

An Internet Service Provider (ISP), like Zen.

Jitter

Jitter generally refers to inconsistent network performance, usually caused by congestion. When lots of people are using the same network, packets of data can arrive at your device at different times, leading to an inconsistent (or jittery) connection. You might experience jitter as buffering or stop/start audio and video.

Kbps

Kilobits per second. A measure of bandwidth, like Mbps and Gbps. As 1 Mbps is equal to 1,000 Kbps, Kbps is now rarely used.

Latency

The delay before a transfer of data begins following an instruction. Latency is important because it affects your online experience. Low latency usually indicates good network performance, and high latency the opposite.

Mbps

A measure of bandwidth, like Kbps and Gbps. 1 Mbps is equal to 1,000 Kbps. 1,000 Mbps is equal to 1 Gbps.

Modem

A MOdulator-DEModulator (Modem) is a device or program that enables a computer to transmit data over, for example, telephone or cable lines.

Ofcom

The Office of Communications. The independent regulator and competition authority for the UK communications industries. www.ofcom.org.uk

PTSN

The Public Switched Telephone Network (PSTN) is also known as the “landline” and is reaching obsolescence. It will be switched off (along with the ISDN network) in January 2027. At which point, all services that use it, like ADSL and FTTC, will have to move to digital alternatives, like SOGEA or FTTP.

Router

A network device that splits an internet connection. The router in your home allows you to connect multiple devices through Ethernet wires or via WiFi. With wireless connections, the closer the device is to the router the better the signal (and therefore performance) tends to be.

Repeater

A device that amplifies the WiFi signal from a router to improve performance.

SOGEA

SOGEA is an all-digital replacement for Fibre to the Cabinet (FTTC). It’s very similar in terms of speed and reliability, but because it doesn’t have a landline it is not affected by the PSTN switch-off.

Upload

The movement of packets of data from a user to the internet, usually expressed in Mbps. Broadband performance is often expressed in terms of download speeds, but upload speeds - though usually slower - are also important.

Wi-Fi

A wireless connection to the internet. Wi-Fi uses a wireless access point to connect mobile devices, such as laptops or handheld devices, to a local area network (LAN). These wireless “hotspots” are commonly used in homes, coffee shops, airports and other public places to share an internet connection.