Broadband acronyms – What do they all mean?

For the non-technical person, acronyms used when buying broadband can be confusing. This guide aims to explain what some of them stand for and mean.
ADSL – Asymmetric Digital Subscriber Line
This is the “normal” broadband service offered by most ISPs. Asymmetrical means the upload speed is slower than the download speed. The maximum download speed is generally “up to” 8Mbps. The maximum upload speed is generally 832Kbps
ADSL2+ – Asymmetric Digital Subscriber Line
This is the newer broadband service offering by some ISPs that utilise LLU or 21CN. Asymmetrical means the upload speed is slower than the download speed. The maximum download speed is generally “up to” 24Mbps. The maximum upload speed is generally 2.5Mbps.
SDSL –  Symmetric Digital Subscriber Line
Similar in functionality to ADSL, SDSL allows the same upstream and downstream speeds. SDSL does not have the same wide availability as ADSL and is generally more expensive.
FTTC – Fibre to the cabinet
Fibre to the cabinet allows faster ADSL speeds by the telephone company (normally BT in the UK) laying fire optic to the street cabinet. The service is then connected to your property via the old copper line. This shortens the effective distance to the exchange. The maximum download speed is generally “up to” 40Mbps. The maximum upload speed is generally 10Mbps.  Availability is not widespread at the moment but more exchanges are coming online weekly. The installation also requires an engineer visit to the property.
21CN – 21st Century Network
BT’s next generation network, which is currently being rolled out nationwide with completion due by 2012.
ISDN – Integrated Services Digital Network
An older alternative to ADSL – ISDN is mainly used for digital switchboards for voice these days.
LLU – Local Loop Unbundled
An LLU ISP has installed their own equipment in telephone exchanges and just use the BT line to your premises. This effectively bypasses the BT wholesale network after the exchange.
Leased Line
A dedicated 1:1 hign availability connection with service level agreements providing direct connectivity from premises to the ISP – effectively bypassing the telephone system. Leases lines are perfect for mission critical scenarios. Leased lines can be costly to install and rent.
WBC – Wholesale Broadband Connect
This is BT’s wholesale service to ISPs offering ADSL2+ services as an alternate to LLU
Wireless Broadband
Not to be confused with 3G Internet dongles or Wifi – We are able to offer high speed (up to 100Mbps and more) symmetric wireless “leased lines” in the Manchester, Liverpool, Leeds and Birmingham areas (depending on line of sight location). Wireless broadband is a cheaper alternative to a “proper” leased line but still provides service level agreements.