[Elecraft] [OT] K9YC's Serial Cable question

Don Wilhelm w3fpr at embarqmail.com
Tue Jun 7 16:14:27 EDT 2011


  Jim,

I could not assure anyone that the Signal Ground (pin 5) is connected to 
the shell of the DB9 in each and every computer or USB to RS-232 
adapter.  In fact I am holding an adapter right now that has no 
continuity between pin 5 and the shell.  That adapter will not work with 
your suggested connections because there is no signal return path.  What 
about those who use plastic bodied connectors?  It will not have a 
return path through the shell for those either.

The signal return path for RS-232 must always be on pin 5 - whether the 
shell is grounded or not, it will always work.

73,
Don W3FPR

On 6/7/2011 2:35 PM, Jim Brown wrote:
> On 6/7/2011 9:06 AM, Brian - N5BCN wrote:
>> For UNSHIELDED twisted pair CAT5:
>> The K2 instructions use Pin 5 for the signal return lines.  Using K9YC's
>> method, would I connect the return lines to the DB9 chassis, and then bond
>> Pin 5 (or Pin 1, or both) to the chassis also?
> Do not use pin 5 for the return, use the shell of the DB9.
>


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