DSL is an asymmetric communication technology designed for residential users; it is not suitable for business.The existing local loops can handle bandwidths up to 1.1 MHz by removing the filter at the end of line of telephone company but, limitation because of distance between the residence and the switching office, size of cable. DSL voice : channel 0 is reserved for voice.Idle : channel 1 to 5 are not used; gap between voice and data communication Upstream data and control : channels 6 to 30 (25channels); one channel for control.Downstream data and control : channels 31 to 255(225 channels); 13.4 Mbps; one channel for control.Cable Modem Traditional cable Networks community antenna TV (CATV).Communication in the traditional cable TV network is unidirectional.Synchronous Digital Hierarchy : SDH SONET is a synchronous TDM system controlled by a master clock