Re: Adtran async/sync DSU 5600 with PM's

Robert Hanson (roberth@cet.cet.com)
Thu, 28 Sep 1995 16:51:02 -0700 (PDT)

so is all this all about load balancing 2 28.8 modems for a feed to a
remote pop or net/subnet??? is the reason to do this "telco" cost in that
area cause otherwize it seems that if you look at the overall cost factor
of doing it with the 2 28.8s vrs one 56k adtran and etc equip it sounds
like a waste of time/money? clue me in here... maybe its just that i dont
get screwed by my telco for service cost??? speed vrs cost??

On Thu, 28 Sep 1995, Matthew Zahorik wrote:

> On Thu, 28 Sep 1995, Dick St.Peters wrote:
>
> > > They are half-duplex.
> >
> > I have to aknowledge being wrong.
> >
> > That leaves the poor peformance of a 28.8 dialup compared to half that
> > of a 56k line unexplained. Modem turnaround time is the explanation I
> > have often seen given.
>
> It's the latency introduced via. what, in reality, is a 2400 baud connection.
>
> Even a 28.8Kbps is 2400 *baud*. An analog line can't switch states
> faster than 2400 times per second. You get 12 bits/baud by using 12
> distinct signaling frequencies.
>
> The fastest a bit of information can make a round trip is 2 * 1/2400 seconds.
>
> A 56Kbps connection is 56000 baud. A bit takes 2 * 1/56000 seconds
> theoretical minimum round trip time.
>
> - Matt
>
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