Behold the "Telephone That Registers Calls in One's Absence." It sounds like something from the Onion, but it's an actual invention from the pages of Scientific American in 1919. The brainchild of a nameless "California inventor" (so much for his fifteen minutes of fame), the device was a recording telegraph made to be installed in "the base of the telephone instrument." It sounds ingenious, but there were two major drawbacks.
First, it required the operator (remember her?) to plug "the telephone receiver out," then put the telegraph into the circuit if no one was there to answer the call. Next—and this was perhaps the fatal flaw—she had to translate the caller's message into Morse code, which was "recorded on the [paper] tape in the base of the telephone." So, when you returned home, all you had to do was decode any messages "with the aid of the code card supplied with the apparatus." Of course, human agency meant that simple miscommunication or a lack of Morse code literacy turned "Bob says to call back" into "Babs says the caulk's bad" in the wink of an eye, which is probably why successful early answering machines were the ones that recorded messages verbatim onto a magnetic wire.