When I was involved with private-loop provision, what I noticed here in northern Nevada is that the provisioning of T1 circuits moved from baseband signalling to SDSL. >From the standpoint of cable management, the splatter from SDSL was MUCH lower than the splattering of baseband T1, so instead of being limited to a single T1 circuit >per 25-pair bundle, you could have several circuits.
TIA T1Q1 has quite a lot to say on this.
Absolutely correct, the SDSL gets you around a lot of the inductance problems with baseband T-1s. For quite awhile now most carriers deliver T-1s using SDSL smartjacks. Some are single pair 1.5mbps bidirectional and on longer circuits they use two pairs each running 768 kbps. That technology is what DSL home service developed from and predates the ADSL standards which were create explicitly for internet users that want more downstream than upstream. Steven Naslund Chicago IL