Re: serial port communication problem with null modem

From: Floyd L. Davidson (floyd_at_barrow.com)
Date: 02/18/05 

Date: Thu, 17 Feb 2005 16:21:52 -0900

Alex van Denzel <vandenzel@hotmail.com> wrote:
>Floyd L. Davidson wrote:
>
>> "prakash" <prkumi@rediffmail.com> wrote:
>>
>>>I am trying to establish a connection b/w port1 and port2 ( com ports
>>>of PC)
>>>/dev/sttyS0 and dev/sttyS1
>> Generally, data sent via a serial port on one computer is not
>> synchronized to the cpu of receiving computer, but when you send
>> and receive with ports on the same computer, the cpu necessarily
>> services each in a sequential order and can never do both at the
>> same time. The two ports are timed in lock step...
>
>I have had success using two minicom sessions on the same PC
>with a null-modem cable between the two serial ports (neither
>Linux nor HP-UX, but NetBSD, but that's not the point).

Sure, but minicom is well written... and was developed using
two separate computers.

The point is not that you can't do it; just that if you develop
software (and particularly if you are learning how serial port
data comm works at the same time), what you'll find with two
ports on one system is a *very different* beast than what you'll
find using two completely different systems. 

-- 
Floyd L. Davidson           <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)                         floyd@barrow.com

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