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

[Randy Kramer]

On Thursday 22 December 2005 12:56 am, Ricardo SIGNES wrote:
> * Pat Regan <thehead at patshead.com> [2005-12-22T00:44:42]
>
> > Ricardo SIGNES wrote:
> > > Your modem is probably full duplex, meaning it can transmit and receive
> > > at once.  That does NOT mean that it can transmit and receive 33 kbps
> > > each way.  It can receive a transmit and receive a total of 33 kilobits
> > > per second.
> >
> > Sure he can, assuming the line is clear both ways.

Hmm, thanks to you both, but now I'm (as) confused (as I was before).

Maybe I'll try to read V.34?  Anyway, some specific questions:

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

> > 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)?

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.

Randy Kramer

> > I don't think that was a technical limitation of the 
> > modem, but a limitation of the phone lines.  I stopped paying attention
> > after v.90, but I believe I remember reading somewhere that you can now
> > do 56k both ways.
>
> I don't know of any standard that allows that.  Beyond v.90 I only know
> v.91, which was strictly a four-line protocol.