RE: Re: CurrentCost serial cable wanted

["Paul Gordon" <paul@xxxxxxxxxxxxxxxxxxxxx>]

I was, of course, typically running connections at just 9600 baud,
which
was pretty leading edge then!!... Hmmm, I wonder if I still have my
trusty breakout box ferreted away anywhere...

Paul G.

-----Original Message-----
From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
Of Kevin Hawkins
Sent: 05 March 2009 10:48
To: UKHA Group
Subject: Re: [ukha_d] Re: CurrentCost serial cable wanted

Me too .. so I'm hopeful this would work over 40m.

The RS232 spec/recommendations do seem overly pessimistic in terms of
what actually you can achieve in practice. The new CC128's use quite a
fast serial speed however (57600 baud) . Typically when you exceed the
workable distance you will still get communication but might see an
occasional mangled character or all mangled.   If you are not using a
parity checked transmission these are problematic, even parity checking
only catches half the character errors and so a checksum (CRC) is
recommended. . Reducing capacitive coupling between TX and ground can
help as can shielded cable.  Try combinations of twisted/untwisted pairs

and an earth shield, grounded at one/both ends.  If you are seeing
nothing I might expect a wiring misconfiguration.

K

Paul Gordon wrote:
> In years gone by, I used to patch serial connections over way longer
> distances than that... I used to run serial terminal connections to
> mainframe & Unix host machines over the length & breadth of a
6 storey
> building just by patching RS232 cables over the CAT5 structured
> cabling... It used to work just fine over hundreds of feet...
>
> Paul G
>
> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> Of craig
> Sent: 05 March 2009 07:50
> To: UKHA Group
> Subject: RE: [ukha_d] Re: CurrentCost serial cable wanted
>
>
>> The signal does go the 15m or so from the kitchen to my patch
panel,
>> but the 25m from the patch panel to Node0 doesn't work - the
combined
>> distance is obviously a non-started.
>>
>
> When you say 'signal' are you extending the RJ45 connection direct
from
> CC,
> or the DB9 serial connection after conversion?
>
> I'm guessing, but if you are extending the RJ45 CC connection, its
only
> 3.3v, so distance will be more of a problem than if you extended the
DB9
> using converters that is true rs-232 voltage.
>
> Or could you not use an additional CC display unit, one for 'display'
> one
> for 'data' serial connection?
>
>
>
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