On Feb 25, 6:53*am, Frank Paynter wrote:
I installed a TT21 last fall and *thought* I had it configured and
working properly. *I fired it up this morning in preparation for the
start of the soaring season, and it came up in configuration mode
instead of the normal operating mode. *I ran through the configuration
sequence again, turned it OFF when prompted, but it still comes up in
config mode when I apply power.

As a possible data point, I still have all zeros in for the system
Mode S 'address' *- could this be the problem? *If so, how does one go
about acquiring an address?

TIA,

Frank (TA)

Frank,
Your address is part of your aircraft registration information. You
can get it he
http://registry.faa.gov/aircraftinqu...m_Inquiry.aspx
You will need to convert it to hexidecimal for input into the TT21.
I seem to recall some talk of the TT21 not working without the
address, so this may be your problem.