The transmitter and receiver are jointly optimized with a minimum average-probability-of-error criterion. The transmitted waveforms are binary and the receiver is nonlinear with zero memory. Errors are due to additive, Gaussian noise, with independent samples, and adjacent symbol interference. The channel impulse response is assumed to be known and time-invariant. The optimum waveforms are given by the eigenfunction corresponding to the maximum eigenvalue of a symmetric integral operator. In addition, the optimum receiver is given for extensive inter-symbol interference, and its probability of error is formulated. The results are applied to data representing an experimental, bandpass, telephone channel with quadratic delay. This example shows approximately 5.5-dB performance improvement over a rectangularly pulsed carrier and standard correlation receiver. The system developed here tends to minimize the effect of inter-symbol interference while transferring maximum energy through the channel. This is contrasted with systems that eliminate the inter-symbol interference at the expense of a reduction in energy transferred.