When replacing the TRA3500 with a RA4500, the only parts that can be reused are the antennas. The change will require different length cables, replacement of interconnect wiring form the RA4500 to an indicator and the indicator needs to be replaced with the RAD40 or other PFD with ARINC 429 input. The original TRI40/TRA3500 system only uses a single coax to interface them together, while the RAD40/RA4500 system will need power, ground and a twisted shielded pair for the data line.

You will also need to consider if the current TRI40 has any audio interface. The RAD40 does not have an external audio connection. If your installation requires an external DH audio output, then an additional tone generator will be needed.

However, if you are only replacing the TRA3500 system and will not be interfacing it to any other equipment, the RA4000 system will perform the same function at a less cost than the RA4500.