In Pride and Prejudice, when Mr. Collins returns to the parsonage after paying his initial respects to Lady Catherine's two nephews, he unexpectedly brings the gentlemen with him.
Elizabeth had scarcely time to disclaim all right to the compliment before their approach was announced by the door-bell, and shortly afterwards the three gentlemen entered the room. (ch. 30)
Why would they hear the door-bell? Would Mr. Collins ring the bell to enter his own house? Would a servant need to be called to do honour to the guests, so this, despite being called a 'door-bell,' is really servants' bell?
In Northanger Abbey, ch. 28, Catherine and Eleanor hear the 'house-bell,' and assume it is the arrival of Eleanor's eldest brother, and later discover it to be Eleanor's father, instead. Is this a door-bell, too? Would the returning proprietor, or his heir, need to ring his own house's bell, to beckon servants, or to give notice that their rooms need to be readied, etc.?
I have been having fun, thinking of Hunsford and Northanger Abbey having a little bell over the door to notify the inhabitants of the door opening, like a little, family-owned shop today! If anyone knows the reality of this detail, I am metaphorically all ears!