What is ADSL Max?

ADSL Max is the latest offering which provides a downstream speed of up to 8 Mbps. At the same time, it provides an upstream speed of up to 832 Kbps (448 Kbps for home packages). This technology was rolled out to the majority of exchanges in April 2006. Whereas with standard ADSL connections, where you usually sign up to a particular speed, eg 512k, 1Mb or 2Mb, ADSL Max will be a variable connection speed. This means that you sign up to an "up to 8 Mbps" service - and the length / quality of your phone line will determine how much speed you actually receive.

For a complete guide on how ADSL Max works, click here.

What is ADSL2+?

ADSL2+ is another type of ADSL, this time providing speeds of up to 24 Mbps. ADSL Max can only provide speeds of up to 8Mbps, thus to obtain anything faster, ADSL2+ is the only way to go. The ADSL2+ service is not currently available in the UK through BT's network, although some ISPs are starting to offer ADSL2+ speeds of up to 24 Mbps over their own network (Be, UK Online etc).

Can I receive ADSL Max or ADSL2+?

All ADSL connections rely on two main "figures", that are unique to your phone line. These are known as SNR and Attenuation. SNR is how much signal you are receiving as opposed to noise on the line, and attenuation is how much loss of signal you have on the line. The SNR will often fluctuate at different times of the day, so it is difficult to monitor, whereas attenuation is fairly static, and depends on the actual length of your phone line between your premises and the BT exchange. For SNR, higher is better (meaning not much noise on the line), but for attenuation, lower is better (meaning not much loss of signal on the line).

The SNR will reduce as you connect at higher speeds. For a reliable service, the SNR has to be above 6, and ideally above 10.

For example, if you have an SNR of 10, and you are on a 2 Mbps ADSL service, you would not gain very high speeds from ADSL Max /ADSL2+, as if you where to connect any faster, the SNR would drop to about 6, causing disconnections and download speed problems. But if you had an SNR of 30 on a 2 Mbps ADSL service, you could probably receive the full 8 Mbps on ADSL Max, which will cause the SNR to drop to about 8-10, just enough to operate reliably. Lines that are quite close to the exchange, eg <2km, should be able to receive speeds of "up to 24 Mbps", once ADSL2+ is launched. Once again, there is no sure fire way to find out what your phone line will support, until a service is installed on the line.

One thing worth noting is that for the ADSL Max and ADSL2+ services, there will not be a "limit" on whether you can sign up to it or not. You will simply be provided with the service, and the equipment at the exchange will automatically determine what speed your line is capable of providing each time you connect, based on your SNR. This is welcomed, as while it may connect at a slower than expected speed, it will help stop your connection from disconnecting due to a low SNR. I am sure most people would rather have a stable, always on (slightly slower) connection, than a (slightly faster), intermittent one.

More information will be placed on this page as soon as it becomes available. If you know of anything we have missed, or have any corrections, please feel free to contact us.