Early adventure games were frequently played via terminal systems, simple keyboard/display combinations that connected to an expensive central computer usually owned by a university or a large company. The terminal communicated with the server via an early modem. The earliest modems didn't connect directly to the phone jack, they used a device known as an "acoustic coupler" - literally a cradle that you would place the phone handset in, with a speaker and microphone set up to "talk" to the phone in binary.

The Dial-a-Grue device is the creation of Mitch Patenaude. It consists of an original unmodified terminal connected via a classic-style phone with a retrofitted amplifier which receives its data from an unmodified acoustically coupled modem. Although the modem talks to a coaster-sized modern computer running the actual game through Ubuntu Linux, the overall impression is very similar to the method that people would have originally used to run Zork.