Need some guidance (CAN24TST120 VS MIL C-27500)

[Dream to fly]

Trying to get all the needed materials and supplies to do this install and after reading the STC I am totally confused.  2 years ago MIL C-27500 twisted pair was an accepted connection method between the G5s, GMU11, and the GAD29B.  Today the GFC500 is requiring CAN24TST120 to link the CAN-BUS.  So my question is I obviously have to use the new CAN24TST120 to link the autopilot system can-bus but when it daisy chains to the previously installed network can it be linked to the Mil C-27500 or do I have to remove all the old twisted pair and install the new requirement?   The STC isn't clear and as long as the termination is 120 ohm at each end then is that the requirement or is it actually the material being used to meet the STC being the requirement.  

[jetdriven]

I think Garmin’s position is before G5 revision 11, if you started the install you could continue using the wire specified in that manual. But anything added after that has to be the new stuff. 

[jamesm]

I have been told by the Garmin dealers that if you plan on Installing the GFC500 autopilot which requires  the  special CAN bus cable. something like $4 to $5 a foot. I believe there is  120 ohm load in the cable not sure of the specifics as how it's made or made different maybe another layer of shielding but it does have different electrical  properties than the MIL C-27500.

 

Edited January 2, 2021 by jamesm