[Elecraft] K3/K2: RS-232 cable

[Don Wilhelm]

JT and all,

Pins 2 and 3 are not swapped on the K2 either.  The problem is that the 
K2 used the nomenclature differently than the K3.   The K2 used 'TXD' to 
denote the line *it* was sending on and 'RXD' to denote the line it was 
receiving on.  The K3 apparently uses the opposite nomenclature and 
labels *its* data *output* line 'RXD (that is correct for a DCE device).
Pin 2 is the data from the DTE (K2 or K3) to the DCE (PC) and is 
normally termed RXD.  Pin 3 is data from the DCE (PC) to the terminal 
device (DTE) and is normally labeled TXD.

This has been a source of confusion when working with DCE devices for as 
long as I can recall.

So *if* only RXD and TXD with Signal Ground are needed for the 
application, yes, the K2 cable (computer end, not KAT100 or XV end) will 
work just fine, but why not pick up a standard serial cable and take 
advantage of the PTT/Keying circuits built into the K2 - that will work 
with no external keying devices.

73,
Don W3FPR

JT Croteau wrote:
> On 10/11/07, Julian G4ILO <julian.g4ilo at gmail.com> wrote:
>   
>> As far as I remember, the K2 serial cable was just a standard 3 wire
>> cable,
>>     
>
> Yes, but the K3 is wired differently.
>
> On the K3, pin 2 is RXD and pin 3 is TXD
> On the K2, pin 2 is TXD and pin 3 is RXD
>
> Also, some K2 serial cables use additional pins for things like XV and
> KAT100 control.
>
>