[CLUE-Tech] Ricochet is in Denver

[Jed S. Baer]

On Tue, 03 Sep 2002 16:22:12 -0600
David Anselmi <anselmi at americanisp.net> wrote:

> Jeremiah Stanley wrote:
> > 
> > One thing to keep in mind is that there is a difference between Kbps
> > and Kb. This is a marketing discrimination that distorts what they are
> > advertising. A Kb is a 1024 bits per second, while a Kpbs is one eigth
> > that size or 0.125 Kb. This explains why modems are 56k but pull about
> > 6-7k/sec.
> 
> As Jed says, the difference is bytes/sec (Bps) or bits/sec (bps).  K 
> means either 1000 or 1024 and it is difficult to tell which is meant.
> 
> In the modem world, at least originally, there were 10 bits per byte 
> (most connections were 8n1--eight data bits, no parity, and one stop 
> bit--plus one start bit for a total of 10).

Dangnabbit! I how could I forget about the start bit. I used to mess with
stuff all the time, back when an unofficial part of my job was configuring
modems and muxes. (Remember mutliplexers? Sure you do!)

> So 2400bps was 240Bps. 
> With the faster speeds sending several bits per baud and with DSL and 
> cable waveforms differing from RS232, I don't know how their bps convert
> to Bps.  But a factor of 8 seems reasonable.  I've seen that suggested 
> before, but it ignores any framing bits (there are always at least 40 
> bytes in a TCP packet, but those are usually counted as data when 
> talking about throughput).

I'm not really sure it's a matter of multiple bits per baud, but more of
an multi-channeling effect using different carrier frequencies. I could be
wrong about that, however.

jed
-- 
We're frogs who are getting boiled in a pot full of single-character
morphemes, and we don't notice. - Larry Wall; Perl6, Apocalypse 5