Symmetric - EFM Overview

2 – 8 symmetrical copper circuits

EFM uses multiple copper circuits from the BT exchange and offers symmetrical speeds to 40Mb although realistically few sites will be able to get more than 10Mb. Compared to fibre Ethernet this copper Ethernet service typically has lower cost and a much shorter lead time. It also has inbuilt resilience as the loss of a single copper circuit will simply result in a reduction in speed rather than a total loss of service.

EFM is available from multiple service providers with differing offers (see Technical). Most will provide a guaranteed speed with SLA’s. Overall coverage brings this technology to about 50% or businesses. For enabled exchanges the lead time is typically 5 weeks but for those still in the planning phase the lead time can stretch out to 18 weeks.

Because EFM is uses copper the speed degrades with distance from the exchange; just like ADSL. Based on distance most providers will agree on a contractual speed and take full responsibility for delivering that speed, even if it means adding more circuits than originally planned.