Short for
Digital Subscriber Line Access Multiplexer, a mechanism at a phone company's central location that links many customer
DSL connections to a single high-speed
ATM line.
When the phone company receives a DSL signal, an ADSL modem with a POTS splitter detects voice calls and data. Voice calls are sent to the PSTN, and data are sent to the DSLAM, where it passes through the ATM to the Internet, then back through the DSLAM and ADSL modem before returning to the customer's PC.
More DSLAMs a phone company has, the more customers it can support.