[rightrudder]

I'm hooking up my GRT Sport SX system and had a question about two serial connections...to the transponder (GTX 327) and to the EIS. No mention about shielded wire here in the GRT literature, but the transponder's serial port is pre-wired with the shielded stuff.

My routing keeps these serial wires away from both antenna coax and strobe wires.

 

[rleffler]

In most cases, shielded wire is preferred. Some will suggest it isn't required, but as a former audio engineer I shielded all my rs-232 lines. Just make sure that the shield is only terminated at one end or you'll create a ground loop, which has the potential of introducing noise into the circuit. It may not significantly impact your EIS, but it will your intercom.

 

[Walt]

Just to clarify:

Shielding data wires is standard practice to prevent digital noise from eminating from the wires. When shielding data lines (232, 429) both ends of the shield need to be grounded.

For audio wires only one end of the shield is grounded generally at the audio panel or radio.

 

[jdeas]

How I remember it

Shield both sides to keep noise in the cable (digital lines etc)
Shield one side to keep noise out of the cable (audio lines)

 

[bruceh]

Or just use twisted pairs for serial data? All of the Dynon serial lines are twisted pairs.

 

[lrgabriel]

I used shielded twisted pairs grounded at both ends for serial connections, and I used AC 43.13 Ch 11 Para 89 as my reference for that decision.

With respect to audio wiring, I agree that manufacturer guidance takes precedence and they should only be shielded at one end.

Good luck!

 

[rightrudder]

Perfect. Thank you for the useful replies!