I am wiring a dual HDX setup with an ACK E-04 ELT (not yet purchased). Serial ports 1,2,3, and 5 are used (VPX, Transponder, ADSB, GPS). So, serial port 4 it is, leaving me with no spare for future expansion. The ELT will be in the rear battery area of an RV-8. Can I just run unshielded...