This is extremely helpful information…….. i do have a question, in the diagram where it says third party serial data device , is that referring to a Garmin GPS for example or another manufacturer Transponder etc etc.
Correct. Any of the 5 ea. serial ports can be used with any serial device, as long as Skyview is configured properly (baud rates, type of data, (sentence structure, i.e NMEA) parity, etc.) and protocols for each device are set the same (Skyview <-> Garmin GPS).
Also - the Skyview serial ports do not have to be used bi-directionally. You can connect a device that receives serial data only from Skyview without transmitting data back to Skyview. I have a Flight Data Systems FC-10 fuel computer connected to a serial port to receive GPS data from my Skyview HDX. The Skyview receives nothing from the FC-10 but still transmits a data stream out on the same port. If you have the Dynon transponder, ADS-B receiver and/or GPS as shown on the drawing, Dynon recommends you connect to the serial ports as shown but it is not mandatory - those devices will work on any of the 5 serial ports.
Ch. 25 of the Installers Handbook (vers. 16) details connecting serial ports and gives guidance on connecting serial ports from multiple displays in parallel to each serial device connected; details the differences in data sentence structure; etc.