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voip issue plz help

hi guys, i know this is not the voip forum but i m asking any1 who can plz help me with this confusion,

see one of my friend told me that the analog lines that comes to our house are in fact demultiplexed E1/T1 lines into individual analog channels !! means that lines that comes to our house are indeed analog but when they terminate at the CO switch they are actually digital lines (T1/E1), and then another guy told me that this is wrong, the pots lines are totally different and the above concept is wrong, can any1 plz tell me that which concept is correct, if u can plz refer me a link, or a book or any forum that discusses this issue ?? i searched a lot on search engines but didnt find the answer so plz tell me i will be really thankful and if possible kindly refer me some resource that details this issue

thanks a lot in advance


Re: voip issue plz help

Both concepts are correct in their own way. It depends on how the LEC chooses to handle it.

An ordinary POTS (Plain Old Telephone Service) line is an analog line from your house to the CO. Once at the CO the analog line can connect into a piece of equipment probably a channel bank or soemthing like it, which will multiplex 24/30 analog lines into a single digital T1/E1 line which then connects into the CO switch or be multiplexed higher into the digital hierarchy on its way to a switch.

In older COs (really older) it could possibly connect directly into a switch as an analog line. But that is much older technology and is rare at best anymore.

So with regard to the basic phone service to your is analog. Once it gets to the CO, it more than likely converted into a digital format (PCM / Pulse Code Modulation) and multiplexed with others into a T1 and then into a switch.

I looked for link, but also couldn't find anything that may help. Hope this does.