[Ticket Question] ESP Aperta 1 Way Colour Video Door Entry Kit with Door Station

[secware3]

Just moved into house with ESP Enterview 5 and bell only sounds on the outside unit, no ring internally, so very hard to hear. Is that normal? Alternatively if I want to replace it with a newer ESP model using installed PSU what would you recommend and would the new one sound inside or do they need plugin or wired extenders? 

[Secware_Tech6]

The handsets should call when pressing the call button.

Is the handset sitting correctly when on hook as it wont call when off hook.

also the unit may have a mute facility is this enabled?