|ADSL - Asymmetrical DSL||Delivers high-speed data and POTS voice service over twisted-pair copper wiring.||Widely deployed and available with CAP modulation, with downstream speeds up to 7Mbps.||Upstream speed limitations are typically 800Kbps with no rate adaption.|
|UADSL (G.lite) - Universal Asymmetrical DSL||A splitterless vairaint of ADSL intended primarily for the home-consumer mass market.||The first end-to-end standard for DSL that will offer full vendor interoperability.||Not yet available with speed limitations (max. 1.5Mbps/384Kbps asymmetric, 384Kbps symmetric).|
|HDSL-High-Bit Rate DSL||An alternative for T1 and E1 using two twisted-pair copper wires.||Supports symmetric speeds up to T1 and E1 rates and does not require repeaters between subscriber and CO.||No POTS support and requires two wires with no rate adaption. A limited downstream spped (E1 max.).|
|SDSL - Symmetrical DSL||An alternative scheme for T1 and E1 using one twisted-pair copper wire.||Supports symmetric speeds up to T1 and E1 rates and does not require repeaters between subscriber and CO.||No POTS support with no rate adaption and a limited downstream speed (E1 max.).|
|MSDL - Multirate Symmetrical DSL||An alternative scheme for T1 and E1 using one twisted-pair copper wire.||Same as HDSL but offers rate adaption and relaxed distance requirements at lower speeds (21,000 feet at 768Kbps).||No POTS support.|
|RADSL- Rate Adaptive DSL||DSL vairant tht offers automatic rate adaption.||Line speeds can be easily changed to optimize connection or at customer request with a high downstream speed up to 7Mbps.||Slow symmetric speeds less than the upstream speed compared to DSLs listed above.|
|IDSL - ISDN DSL||DSL service using ISDN hardware.||Moves ISDN users off the switched network and allows DSL service where only ISDN is available.||Max. data rate of 144Kbps.|
|VDSL - Very High Bit Rate DSL||Ultra high-speed DSL.||Speeds of up to 52Mbps possible (34Mbps symmetric).||Not yet available and will likely have 1,000 feet to 4,500 feet distance limitation, depending upon the speed.|
Extracted from Network Computing, dated 09/01/98, page 104.
Date of Last Revision: 17 December 2001.