[Elecraft] K2 - KPA100 RS232 interface repair

[Don Wilhelm]

The RJ-45 connector is now defined in the RS-232 standard, as is the 
DE-9 and DB-25.
Of course, Ethernet also uses the RJ-45 connector, as do multi-line 
telephone sets.  Those are *not* interchangeable functions.  You would 
not want to plug an RJ-45 RS-232 cable into your RJ-45 ethernet router 
jack or into your multi-line telephone system.
Make no assumptions about connectors, for they are a "just a connector".

Another example:
The older PCs used the DB-25 for a printer port.  How do you tell the 
difference between a printer port and a 25 pin serial port connector? - 
you refer to the manual for the device in question and look for a 
clearly defined label.
At our church, there is a sound console that has a DB-25 connector - 
should I assume that is a printer port, or a serial port just because 
those are connectors commonly used for those applications - of course 
not - the connector on the sound console is for expansion devices.

So, know what you are plugging into before connecting cables (even if 
they fit) - if it is labeled as RS-232, then plug away, but if it is 
labeled with anything different, check the manual before plugging.  That 
fact goes for any device with a connector, it is not just for the K2.

As another parallel, RCA jacks are used for many purposes - antenna 
connections, audio connections, and yes even power connections. Would 
you plug anything into an RCA jack assuming it was an audio connector 
without carefully heeding the label or referring to the equipment manual?

A connector is "just a connector".  Just because it looks like the 
connector in one piece of gear that you happen to be familiar with does 
not mean it serves the same purpose on everything else.  Take DIN 
connectors as an example - they are common on many pieces of ham gear.  
Why would one assume that a 6 pin DIN connector on a Yaesu transceiver 
has the same pinout as that on an Icom.  I hope I have made my point and 
will belabor it no more.

73,
Don W3FPR

On 8/22/2015 8:31 PM, Bob McGraw - K4TAX wrote:
> The K3S has a RJ-45 connector for the RS-232 communications.  Now 
> that's different!   Of course they supply a cable with a RJ-45 on one 
> end and a DB-9F on the other.  And then to keep everybody happy, there 
> is what appears to be a 15 pin VGA connector that is the ACC connector 
> to provide band data and such.  The manual clearly states "This is not 
> a VGA video connector".
>
> Yes it is very important to read and understand the manual before 
> plugging or inserting any connector into any hole on any radio today.  
> It seems most hams think if it plugs in, then it should work.
>