network termination broadband access (NTBBA)
DSL modems form the broadband network termination of the localloopin the local exchange and at the customer's premises. The local loop must be terminated on both sides with DSL modems.
In the local exchange, the data signals are coded and modulated in the DSL modem in accordance with specific coding procedures. The modulation procedures used are multitone, quadrature ampl itude modulation( QAM) or carrierless amplitude-phasemodulation( CAP).
On the end customer side, the various transmission channels are first separated by a splitter before the DSL-encoded signal is decoded in the DSL modem and made available to the computer or a local network as a digital data signal. The connection can be made via a USB cable. During upstream from the end customer to the exchange, the data is modulated in the DSL modem and transmitted via the splitter in the upstream channel.
DSL modems can be stand-alone devices or combined with WLAN routers to form a hotspot.