On older versions of EHX, it is not possible to assign remote IFB sources from a local panel when using trunked matrices. ( It’s never possible to assign IFB’s located on a remote matrix)
In order to assign the remote sources using a local panel assigning local IFB’s, it is necessary to bring the source audio to the local frame. This can be done using typically IP directs or Dante.
For example, to use an IP direct for this purpose, first, set up an IP direct between the two trunked frames. On the remote frame, create a permanent crosspoint between the desired source and the IP direct using Local Advanced Forced Listen:
On the example above, Dir Tel is the IP direct, and 555 6559 is the audio source. Dir Tel is permanently listening to 555 6559.
On the local frame where the IFB assignment is being made, place the IP direct on the assignment panel. That will now be an assignable source since it is available on the local frame.