From: Adriano (adriano.angelillis_at_gmail.com)
Date: Fri Jan 28 2005 - 16:20:39 PST
Peter,
your words explain why RS232 could transmit data at 230K, the same as a
RS422
As you know, RS-422 works on a binary (crossed pair in the cables)
communication, while RS-232 runs on a single data line,
this would explain why the entire process is more stable on this
protocol.
If i am wrong, please tell me more about it.
A big question is: why the TTL levels coming out from the Newton serial
channel3 literary burn the 5v shifted Max232 adapters connected on it?
Have you got any idea?
Adriano
Il giorno 28/gen/05, alle 23:10, Peter H. Coffin ha scritto:
On Fri, Jan 28, 2005 at 10:36:25PM +0100, Adriano wrote:
> Did you try to set the Keyspan speed in the Keyspan serial assistant
> 'Advanced settings' panel? It's available in OS 9. You could use it to
> have both the ports communicating at higher speeds (230K too), and you
> could also choose the port you prefer to use: printer or modem (labeled
> as 1 & 2 on the Keyspan adapter)
Note that 230k bits per second is exactly what Ron's "24Kbps" is in
bytes per second. 8 bits of data, 1 start bit, 1 stop bit = 10 bits -> 1
byte.
> The Keyspan adapter is a RS422 device, it should be faster and more
> stable than a RS232 device.
RS-422 differs from RS-232 PRIMARILY by allowing for a differential
voltage signalling instead of (only) referenced-from-ground signalling.
You run both at any bit rate your hardware supports, but RS-422 can go
FURTHER. In practical cases, that means a given cruddy cable may be able
to be run faster before start seeing data errors, but it's not magically
and inherantly and by-design faster in the same way that Firewire's
faster than Localtalk. Yes, "should be faster and more stable than
RS-232", but that may not mean what it sounds like you and Ron mean.
-- CS is about lofty design goals and algorithmic optimization. Sysadmining is about cleaning up the fscking mess that results. -- This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries Official Newton FAQ: http://www.chuma.org/newton/faq/ WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/ -- This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries Official Newton FAQ: http://www.chuma.org/newton/faq/ WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/
This archive was generated by hypermail 2.1.5 : Fri Jan 28 2005 - 22:00:01 PST