Any compatible GPS receiver will do fine, no need to run new cabling, existing GPS antenna/connectors will do the job.
wrong, wrong, wrong, wrong
ADS-B as required for IFR requires a C146a GPS source. Period.
CASA are supposed to be running a programme to investigate using C129a. But I'm not optimistic.
Peter 005, we've had this debate before. The King KLN94 is not acceptable for ADS-B. You are misreading AC 21-45 v2.1. The KLN 94 is a C129a device. Soon its only use will be as a boat anchor, along with the Garmin 150 / 155XL & 300 XL.
From the CASA FAQ's :
14. If I have ADS-B connected to TSO 129, will I have to update the box?
Unless the aircraft has a separate approval for ADS-B compliance, the GNSS will require upgrading to TSO C145/146 since TSO C129 systems do not output all the information required for ADS-B.