This paper presents a novel multitone transmission scheme that employs a nonlinear binary code to specify multitone signal constellations. The scheme, which can be viewed as a generalization of M-ary frequency shift keying, is amenable to noncoherent demodulation, and it is therefore useful for communication over fading channels. We determine the performance of this modulation scheme when it is used in conjunction with a Reed-Solomon code for error control. Methods for determining and erasing unreliable multitone constellations are presented and their performance is evaluated when they are used in conjunction with errors-and-erasures decoding. The transmission scheme is evaluated with respect to complexity, bandwidth efficiency, and performance in the presence of Gaussian noise and frequency- and time-selective fading.