Overview

ADSL Max is a broad product set title given to a range of BT Wholesale ADSL products that are rate-adaptive, and are deployed over IPStream and Datastream. ADSL MAX was launched nationally in the UK in March 2006 and offers the best possible speed using existing ADSL standards.

The services enabled customers to get up to 8 Mbit speeds downstream, and 832 kbit speeds upstream along a standard telephone line. The average customer will actually receive 5-6 Mb depending on their distance along the exchange loop. Customers can be directly next to the exchange but as it loops they can be at the end of the loop and receive 512 k broadband or even qualify for none at all.

During the first 10 days after the service has been provided a piece of equipment known as the DLM (Dynamic Line management) unit is constantly assessing the characteristics of the line in order to provide the end user with the maximum achievable speed for their line. In this period the DLM can make adjustments to the DSLAM output power, SNR and bit rate and even apply a form of error correction known as interleaving. Several factors dictate the maximum available speed, such as the presence of noise within the frequency spectrum used by ADSL but chiefly it is the distance from the Central Office (Telephone Exchange) which has the largest influence on the lines performance.

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