It is good to hear you are using the special cable. Do NOT plug a standard serial cable into the AUX IO connector, that can damage both the K2 and the serial port.

First, check to see if the PORT menu setting is ON.
That is in the secondary menu (enter the menu and tap display to get to the secondary menu).

Do you have sidetone on that K2? If not, go to the STL menu setting, Edit the parameter and tap DISPLAY until you hear sidetone. Then test again.

Do you have 12 volts on pin 8 of the DE9 connector? If not, inductor L1 on the AUX board may be open.

On the KIO2 board, check inductors L2, L3 and L4 for continuity.

Those are quick checks. If you continue to have problems, it is likely to be the MAX1406 IC on the KIO2 that is the problem. If you are willing to disconnect a wire in the internal cable to the KIO2 board, I can give you some DC tests to check that IC.


On 10/14/2016 11:40 PM, Brad Brooks wrote:
While I continue to review the list archives, I am requesting feedback from the 
group with regard to possible failure modes of the KIO2 board. This rig is in 
loan to me, with the loaner stating that it was claimed working when he 
acquired it from a previous owner, but had not himself tested serial operation.

K2/100 SN 879

Performed configuration and testing outlined in the KIO2 manual. Tests tried 
with no positive results:
- Known good FTDI serial-to-USB interface
- known good "real" serial port.
- serial breakout cable configured per manual.

I have not yet put pins 2 and 3 on the scope to determine if the board has 
failed. I am interested if anyone else has wrestled, and won, KIO2 failures.

Of course, I am open to configuration and user error on my part. I have been 
prone to foolishness in the past.

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