39Figure 6-2 Confirm whether call key is bound with VTH, as shown in Figure 6-3. Please refer to “7.7.2Facade Layout” for details.Figure 6-3Make a group call from button moduleEnsure that button module has been connected and added to façade layout. Otherwise, thiscall doesn’t exist.Before calling, confirm whether call key is bound with VTH, as shown in Figure 6-4. Press thecall key on button module, to call the VTH. Please refer to “7.7.2 Facade Layout” for details.