Actually, it's ADSL:

Most phone companies that offer DSL are actually offering ADSL (Asymmetrical Digital Subscriber Service). Essentially it means that the ADSL bandwidth is not equal in both directions. Usually, the service is stronger for receiving info as apposed to sending it. ADSL tends to be offered in areas that are equipped with phone lines, but ill-equipped for cable broadband. The biggest advantage to ADSL Broadband is it usually is offered at a lower cost than other broadband services. Which comes in handy when trying to set up a small business for the superhighway.