According to my function test as well as finally doing an oscilloscope test they actually are TX4 (pin 8) and RX4 (Pin19). It took me three weeks to figure this out to get the iEFIS Extender to work. It cost me $100 to send the Extender out for service (recommended by the US dealer) and and finally the purchase of this cheap ($75 USD) oscilloscope to verify my suspicions.
Here is how it was tested. Turn off iEFIS extender in Hardware setup so that the Serial test would work on port 4. Enter Serial Test mode and check to see which pin is being transmitted from vis the oscilloscope. TX1, TX2, and RX4 (I forgot to test TX3) all had the same test pattern wave form while TX4 had no signal.
- MX1_RX4-test-sm.jpeg (163.28 KiB) Viewed 2181 times
3 weeks, $100 wasted on sending out the Extender, $75 oscilloscope to test, finding a problem that may help others.
Seems like MGL should buy me lunch or something. How about it @rainier ?