so that I could understand the working of the internet (line wise)
I think the subject material that you may be specifically looking for would be entitled adsl or vdsl. Unfortunately there isnt a dummies guide that Im aware of. I have several text books on Broadband technologies, but tbh they are all very much in depth and also expensive. I don't think I'd recommend any of them as they cover a lot of irrelevant stuff and often assume a higher level of understanding.
The internet is probably your best tool. The reason this site first started was because there wasn't anything anywhere that explained BT's network and how everything all fitted together. I try to 'dumb down' as much as I can some of the technical stuff to what is hopefully a level that can be understood by a layman but still contain a bit of the stuff you need to know. - there was no wikipedia back then either.
I'm perhaps a bit biased but either the tutorials on the main site or wiki are likely to be your best bet. I know that several ISP's use the main site as training material for their staff. The ADSL section is by far the busiest part of the whole website.
As regards to reading line stats, there are no definitive tutorials for that Im afraid as that is more of a skill that gets picked up over years of looking and comparing line stats. I do include some of the basics, but you cant do a specific tutorial on it all because you have to look at the whole picture. Unfortunately we see too many cases where someone panics when something changes by say 1dB, but theyve not looked at the broader picture and realised that it was in the realms of normality. Reading line stats is a black art and even I frequently go on gut instinct because you get 'a feel for the line'. I think even trained JDSU experts also do the same.. and why there is a lack of advanced guides too.
So where to start?
1). Probably look at the diagram -
How does FTTC work. which gives you an indication of the physical layout.
2). The more meaty stuff that you need to know is contained in
ADSL technology and DMT. Although it says ADSL the same theory applies for VDSL.
3). Re Line stats - you definitely need to read
How to interpret your Line Stats. In particular you need to get your head around SNR, SNR Margin & Target SNRm which are 3 different things but related. I think thats probably the hardest part, and the bit most people find the hardest to understand, but if you can get your head around those 3 then you are well on your way and the other bits are (usually) more straight forward.
4). Line stats Explanation attempts to give a brief explanation what each of the figures are.. its not exhaustive, because theres some figures that even we dont know
If you want more info just yell.. We have a decent mix of people on here with various backgrounds, each of us acknowledge that its impossible to know it all because the subject is too broad [pun intended], but the benefit of the forums is that because we have people with those various backgrounds, it all comes together as a team.
