Noun
(electronics) symmetric digital subscriber line
A communications system (or part thereof) characterised by moderately high speeds, the same in each direction
Source: en.wiktionary.orgAlso, some variations of DSL (such as SDSL) use synchronous serial connections. Source: Internet
Engineers developed high speed DSL facilities such as High bit rate Digital Subscriber Line (HDSL) and Symmetric Digital Subscriber Line (SDSL) to provision traditional Digital Signal 1 (DS1) services over standard copper pair facilities. Source: Internet
SHDSL), ITU-T G.991.2, standardized successor of HDSL and proprietary SDSL, up to 5,696 kbit/s per pair, up to four pairs * Asymmetric digital subscriber line (ADSL), umbrella term for xDSL where the bitrate is greater in one direction than the other. Source: Internet
In symmetric digital subscriber line (SDSL) services, the downstream and upstream data rates are equal. Source: Internet
This is true both for ADSL and SDSL variations. Source: Internet