A performance analysis of (XY) multiple pulse position modulation (PPM) systems, in which X denotes the number of data slots and Y the number of pulses, operating over a plastic optical fibre channel has been described. The effects of receiver noise and channel dispersion are accounted for and the manner in which the erasure, wrong-slot and false-alarm errors affect the system performance is examined. The receiver/decoder uses slope detection and a maximum likelihood sequence detector. As the analysis of any (XY) multiple PPM system is extremely time-consuming, a novel automated solution was designed to predict the equivalent pulse code modulation (PCM) error rates of specific sequences and to simplify the task. A measure of coding quality that accounts for efficiency of coding and bandwidth expansion has also been proposed. Using this measure, original results show that a (126) system is the most efficient for a wide range of bandwidths.