Telecoms providers: ADSL, now with added benefits using ADSL2 or ADSL2+
Contrary to what many consumers could believe, ADSL technology has kept evolving to become faster, more reliable, more feature-rich internet connection. Even though not always marketed with their proper names and often collectively referred to simply as ADSL, ADSL2 or ADSL2+ represent significant improvements over the original standard, bringing added benefits to business and private customers. But just exactly what benefits?
ADSL
A brief roundup is required to understand the technological foundation of this family of data communications.
Basics and price
Asymmetrical digital subscriber lines actually use copper lines also used for telephone communications, but using filters and splitters, at the user’s home and at the telephone exchange, only frequencies not utilized by phone calls carry data. Note that some lines were installed using not the traditional phone lines, but ISDN lines.
The main advantage is that it offered great data speed for the time without the need to install more physical lines, using the existing phone network. Because they are asymmetrical, these lines have a much higher downstream rate (or download speed) than upstream rate (or upload speed) - but this was fine for the majority of private users who download much more than they upload.
The first lines were installed in 1998, and the technology was incrementally improved with several intermediary standards. This technology, through all its subsequently released sub standards, is now widely available with plans costing around £20 per month.
Typical performance range
Depending on the generation, performance range can be:
- Between 1.5 and 12.0 megabits/second downstream rate,
- Between 0.5 and 1.8 megabits/second upstream rate.
ADSL2
This technology was introduced in 2002 and newer developments were added until 2005.
Major improvements
One of the weak points of this type of technology has always been that the further the user is from the telephone exchange, the slower his connection. ADLS2 improved the distance the line can reach from the exchange and the resistance to noise. Besides, it introduced dynamic data rate adaptation, a standby mode, and cut the initialisation time down to less than 3 seconds from 10 seconds.
Typical performance range
Depending on the generation, performance range can be:
- Between 1.5 and 12.0 megabits/second downstream rate,
- Between 0.5 and 3.5 megabits/second upstream rate.
ADSL2+
Most broadband plans on the market today use this technology, which was introduced in 2003.
Major improvements
ADSL2+ really brought significant improvements to the performance of this technology by considerably strengthening permeability to noise. By doubling the bandwidth, this technology actually doubled downstream rates.Also, this leap in speed was made available to any user within 5,000 feet of the telephone exchange.
Typical performance range of ADSL2+
- Between 23 and 25 megabits/second downstream rate,
- Between 1.4 and 3.3 megabits/second upstream rate.
