question
why do DSL modems need to "train"? (be connected and turned on for a longish period of time--ours says 10 days). the only clue the sticker gives is that it has something to do with speed.
training: "A process where two modems try to establish a connection over the telephone (voice frequency) line." from this Paradyne master glossary (pdf). Paradyne is a company, and the master glossary has isp things in it. so: training handshakes with the isp, and optimizes the frequency data is sent at; being able to send data at lower frequencies means that you can send data at a faster rate. "fast retrain" refers to an ability that some modems have to adjust to use more of the bandwidth (take over voice frequencies) when the phone is on the hook, and ignore (attenuate!) those same frequencies when the phone is in use. from this DSL sourcebook, also put out by Paradyne. this doesn't explain why it might take 10 days to optimize.
(this question came up because we just got a Zoom ADSL modem at work.)
