The WiFi Retromodem is a non-destructive replacement of the PCB in an external Hayes Smartmodem 1200 or 2400. Note: while it will fit in the later Smartmodems, the LEDs of the Retromodem in the Hayes Optima series aluminum cases are offset slightly from the letters below. The Retromodem is based on the ZiModem software available on Github. This new version also supports simulated audio dialing just like a real Smartmodem connected to a phone line.
The board can be purchased from this page.