Abstract: An improved envelope tracking and control system for a mail sorting machine of the type which reads a sorting code imprinted on each envelope and deposits the envelope in the proper sorting bin by deflecting a diverter gate associated with the bin. Each diverter mechanism has two sets of photo sensors which sense the presence of an approaching envelope. Tracking circuitry processes the sort code obtained from the envelope and transfers the processed data to the tracking circuit for the next diverter if the data does not coincide with a code that has been preassigned to the diverter. The processed data is held in a latch circuit and is passed on only if the envelope is sensed by the second set of photo sensors. If there is coincidence of the data, a one shot pulse applied to a solenoid deflects the appropriate gate for a predetermined time period that avoids possible damage to the solenoid or to the circuit components.