Obliged in example sentence
Frederick Knott wrote Dial as a play in the early fifties and the Hitchcock film version was released in 1954 BUT the entire plot (our old friend the 'perfect' murder) hinged on the fact that in those days only the upper and middle classes had telephones at all and those were in fixed locations and in this era of jack points and cell phones the idea of someone obliged to answer a telephone located on a desk in front of heavy drapes behind which a murderer was lurking ready to strike when the phone was answered would be ludicrous.