ELT ACK E-04 GPS signal

[Gagarin737]

After install of the ACK E-04 ELT there is a procedure to check the GPS input but it failed. I checked all wires to the ELT (GND/12V/GPS data in). Serial 1 on Dynon is configured as NMEA (BASIC) out with a baud rate of 9600.
Is there more to do for the setup and is there a way to check the NMEA signal going to the ELT?

 

[dynonsupport]

If you have more than one display, make sure that both of the display's serial 1 TX wires are wired to the ELT, and also, that both displays are set up the same way (as you've described above).

Since the ELT doesn't output status that we can read, there isn't any way for SkyView to report that it knows that the ELT is getting data. It's essentially transmitting "in the blind".