Interleaving involves the use of powerful error-correction algorithms to improve broadband speed and stability on long or noisy phone lines. We use it as a matter of course on our broadband lines, including Superfast Fibre lines where the connection between the street cabinet and your home is over a copper cable.
Interleaving helps make your broadband more stable - and in some cases faster - which improves your browsing and streaming experience. However, it can also increase the delay (latency) of your connection by up to 40 milliseconds. If you're just browsing you'll not normally notice this. But it can adversely affect some delay-sensitive applications such as certain online games.
Interleaving can't be switched off for fibre-based broadband lines (such as Fibre 100 and Fibre 250 or Superfast Fibre). But you can ask for it to be switched off on ADSL (copper) broadband lines - although we don't recommend this.