Thanks and a question on modem speeds (was Re: [Lvlug] BitTorrent-Able to upload behind a NAT box?)

[Pat Regan]

Randy Kramer wrote:
> Re: "the line is clear both ways": why wouldn't it be?  I mean it's my 
> dedicated phone line (pair) (but more below).
> 

A line can be more clear in one direction than the other.  I suppose you
can think of it this way.  If you have a noisy piece of wiring at your
house, that noise is introduced into the signal very early on in your
transmission.  From the other end, that noise is introduced very late.

>> > v.90 only transmits downstream at 56k (53k :p).  Upstream is limited to
>> > 28.8 or 33.6.  
> 
> But, is that simultaneous--I mean is my total bandwidth (in that case) 86.6 k 
> (53 + 33.6)?
> 

If you want to measure it that way, yes.  You don't say a T1 is 3 Mbps
even though it is full duplex 1.5Mbps.

Technically the 53/33 Kbps is full deplex, too.  Both ends always
operate at their maximum speed.

> Aside: RCN provides my telephone service.  About a year to year and a half ago 
> (iirc), they came around and made a change to my phone lines.  Prior to that 
> change, the best connection I could ever get (even with a 56 k modem) was 33 
> k--recently, while working on a computer for someone else, I tried out their 
> modem and got a connection somewhere in the 40s (don't recall if it was 41 or 
> 44).
> 
> Anyway, RCN's change was to, at the little box outside the house, disconnect 
> me from the dedicated pairs going back to the central switch and instead 
> install some sort of adapter to connect to the TV cable coax.  I suspect that 
> it uses VOIP or some variant thereof.  So, inside my house I have standard 
> phone lines, at the interface box it switches to VOIP, and, overall, I have 
> better phone lines than the dedicated pairs I had before.  Interesting.
> 

This is interesting to hear about, since in the past I have worked for 2
different phone companies that provided dialtone.  If they are using
voip, or some variation, I wonder how much bandwidth they have to supply
to allow you to connect at 40k+.  I suppose it really doesn't matter,
cable companies have plenty of bandwidth to spare on that coax.

Pat
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: OpenPGP digital signature
Url : http://www.thelinuxlink.net/pipermail/lvlug/attachments/20051222/56529930/signature.bin