Hal Murray <[EMAIL PROTECTED]> wrote: > Does anybody know how DSL works? If I poke around with a scope in my DSL > modem/router, will I find a clock locked to the telco's master clock?
I doubt it. DSL lines come from DSLAMs, not from "real" telco equipment like switches and synchronous digital hierarchy (SDH) equipment where those precise synchronised clocks live. DSLAMs switch and multiplex at the packet or ATM cell level and thus have no need for syntonisation of the actual DSL carrier frequencies. Although I've never poked inside a DSLAM, only customer premises equipment (CPE), I would expect that the clock for the per-line DSL transceivers comes from an ordinary commercial grade crystal oscillator on the line card. There are some DSLAMs on eBay oftentimes and I don't even see where one would connect to a telco master clock. > How many different versions of DSL are there? My personal interest focuses on SDSL, but even that is already a mouthful of flavors: http://ifctfvax.Harhan.ORG/OpenSDSL/ But unfortunately a lot of the original DSL diversity has died out and most of the world has concentrated on the completely boring and uninteresting (to me at least) ADSL/DMT. MS _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
