What does line speed terminology really mean?

What does line speed terminology really mean?

Friday, 15 March, 2019

We start this article with a question. Do you know what your average broadband download speeds are at peak times?

Some people could take an educated guess, but many consumers would be unable to provide an accurate answer.

There’d be even fewer responses to a supplementary question about whether peak time connection speeds deserve classification as standard, ultrafast or somewhere in between.

And queries about whether a connection is FTTC or FTTP would probably be met with a mumbled excuse about having to be somewhere else.

Sifting through the jargon

Line speed terminology is a confusing jumble of abbreviations and interpretations, where X to Y is classed as one thing while Y to Z is treated very differently.

Then there’s the language used – a series of acronyms and technical measurements of things like megabits per second.

At least this part is easy to explain.

Digital data is transmitted in binary bits – the smallest unit of data storage, representing either a zero or a one. Everything our computers do revolves around bits of data.

A megabit is a million bits, so the abbreviation Mbps describes how many Megabits can be transmitted per second.

A megabit is comprised of a thousand kilobits, while a thousand megabits make up a gigabit.

(It’s worth knowing that a byte is a string of eight bits, and this larger unit of measurement is often applied to file sizes and storage devices.

A photo might be described as 5MB – five million bytes – and a laptop hard drive may be advertised with 500GB of storage, or five hundred gigabytes.)

Categorising line speeds

Broadband connections tend to be graded as one of the following:

  1. Standard. Anything between two and eight megabits per second represents the lowest category of broadband recognised by the UK Government. You won’t be offered a package of this speed anymore, but connections sometimes still run this slowly
  2. High-speed. Rather confusingly, this term is used by broadband companies to describe speeds which in truth aren’t especially impressive. Connections between eight and 30Mbps would fall into this category
  3. Superfast. Anything between 30 and 300Mbps is considered superfast by industry regulator Ofcom and the EU. ISPs take a slightly more optimistic view and categorise anything over 24Mbps as ‘superfast’, leaving the exact definition open to interpretation
  4. Ultrafast. An elite group of broadband connections deliver line speeds over 300Mbps. Specialist firms like CityFibre and Hyperoptic are investing heavily in underground fibre cable; Virgin Media also advertise their 100Mbps and 200Mbps cables as ‘ultrafast’.

Standard and high-speed connections usually use copper telephone lines connecting individual homes to the nearest telephone exchange – those green or grey pavement boxes.

When the global web of high-performance fibre optic data cables goes no further than the exchange, these connections are called Fibre to the Cabinet, or FTTC.

The superior alternative is Fibre to the Premises. FTTP involves cables extending directly into your home, so data isn’t slowed down by copper wires on the final leg of its journey.

To reduce line speed terminology, FTTP is often referred to in marketing literature as ‘full fibre’.

Rather like the breakfast cereals which feature this term on their packaging, full fibre broadband is regular and rapid in equal measure.

It’s not much more expensive than FTTC, despite the latter’s restricted performance across phone lines which were never intended as data carriers.

The Holy Grail is line speeds of one gigabit of data per second, and heavy investment in gigabit broadband services is underway around the world.

Line speed terminology in practice

It’s important to understand what a speed of 24Mbps really means for consumers.

Ofcom guidelines stipulate this must be the average download speed achievable at peak times – between 8pm and 10pm.

Because most online activities involve downloading other people’s content rather than uploading our own, line speeds refer to downloads.

Nonetheless, ISPs will soon have to advertise average upload speeds as well.

For reference, Netflix customers are asked to have a line speed of at least five megabits per second, meaning their services ought to be accessible by almost any broadband customer.

Faster connections should be fine for day-to-day web browsing and smartphone gaming, though PS4 and Xbox One owners might struggle to play online titles below 10-15Mbps.

To find out how quickly your line transmits and receives data, visit a broadband speed checker website.

Neil Cumins author picture


Neil is our resident tech expert. He's written guides on loads of broadband head-scratchers and is determined to solve all your technology problems!