The symmetrical data rates of BR-ISDN, HDSL, SDSL and most importantly SHDSL G.991.2 are of special importance for business customers. We discuss their technical characteristics, improved latency and their advantages over ADSL. Voice over Digital Subscriber Line (VoDSL) and the new Channelised VoDSLC are two different approaches to carrying multiple voice circuits over symmetrical and asymmetrical DSL services. We explain and compare these to see which situations each is most appropriate for.
