It will work as it is. The design uses two tones and tone detectors, all you have to do is use one tone for '0' and another tone for '1'. Technically, you can use just one tone and key it on and off but it opens the possibility of stray sounds being misinterpreted. The data rate would be quite low though, probably 100 Bauds or less due to the time the tone detectors need to reliably confirm the presence of the appropriate frequency. For ideas, look up "RTTY" which uses the same principle but a slightly different coding system which you can ignore.
Brian.