The Xantech 282TP looks like this:



The reason to have this setup is mainly as a backup in case something happens to the control system OR in cases of high channel surfing where AMX/Crestron remote batteries just wont last very long (for any model) being undocked. I can attest that i channel surf with best of them and my directv remote hasnt had batteries replaced in 2 years.

These emitters arent made anymore --i picked up a few some ways back. Still, its designed to be able to do exactly what im trying to do. When i searched the forum users reported success with differing control system i.e. elan/RTI with this cable

when Xantech and AMX ends are both connected --only IR from Xantech works
when only either Xantech OR AMX ends are connected --both IR's  work perfect

as pointed out there has to be something in the Xantech setup --dinky link receiver -> 789-44 connecting block thats somehow blocking control via other devices....