Multiple ADSL lines can be bonded to give higher bandwidth; in the United Kingdom, ADSL is sometimes bonded to give for example 512kbit/s upload bandwidth and 4 megabit/s download bandwidth, in areas that only have access to 2 megabit/s bandwidth.
Source: http://en.wikipedia.org/wiki/Channel_bonding
Source: http://en.wikipedia.org/wiki/Channel_bonding