ASR-33 Data Format?

From: Eric Smith <eric_at_brouhaha.com>
Date: Wed Mar 31 17:42:05 1999

Hans wrote:
> I have an 7 KBaud modem over here so, where's your stick ?
> (Hint: server side of an 56K analouge dial in :)
> (small print: the calculation can be done different :)

Megan wrote:
> In this case, it sounds like your modem uses a scheme which
> somehow gets 4 bits across the wire per signal change, so
> 7Kbaud (7000 signal changes per second) gets across 56Kbps
> (56000 bits per second).

No, if it was 7Kbaud and 56Kbps, it would need to get 8 bits per symbol,
not 4. 7000 symbols/second * 8 bits/symbol = 56000 bits/second. Note
that this would require a constellation of 256 distinct symbols (2^8).

However, as previously noted, 56K modems actually operate at 8000 baud,
with up to 7 bits/symbol.

Anyhow, this is OT for another 7 years or so.
Received on Wed Mar 31 1999 - 17:42:05 BST