At ECS 524 the way the xpt (crosspoint) control works has changed. The small blue up/down buttons are used to adjust the local crosspoint level at your panel . This provides the operator with a way to create their own personnel mix of incoming audio. Example the operator can adjust the incoming audio of 4wire-1 to be louder than that of 4wire-2 
This applies to V-series lever keys and rotary panels, as the intercom key on those panels has a separate listen selector and talk selector 
On a lever key / Rotary panel  a) If you program in ECS only the talk side, then it shows thetalk label (the encoder , xpt up/down buttons adjust incomingaudio from the talk label)





b) If you program in ECS only listen side, then it shows the listen label(the encoder, xpt up/down buttons adjustthe incoming audio from the listen label)





c) If you program in ECS  port #1 on the listen side and port #2 on thetalk side, then the talk label is shown by default (and if you press and holdthe AUX vol pot it shows the listen label )(the encoder , xpt up/down buttons adjustthe incoming audio from the listen label)