A Digital Subscriber Line Access Multiplexer (DSLAM) is a mechanism that combines the individual ADSL-signals from subscibers into a single datastream. The combined data is routed to the Internet Service Provider (ISP). The maximum upload and download speed of a subscriber are set up in the DSLAM.
The ADSL signal that is received by a telephone company is splitted in voice and data. The voice signal is routed to the telephone exchange and the ADSL data signal is routed to the DSLAM. An ADSL-modem in the DSLAM extracts the data out of the signal. The data of the subscribers are put together and send to the ISP. The ISP is responsible for the connection to the Internet.