Most of whats posted on this thread relates to Dublin. In country areas, it was very much word of mouth. Generally the local prossie was a poorly kept secret.
In my local town, in the early 80's there was a house with a stuffed pheasant in the window. Gentlemen callers were welcome or not, depending on which direction the pheasant was facing. I don't think the lady had a landline phone, I remember seeing her using the public phone.