An apparatus for receiving a data stream having a plurality of time domain spread spectrum messages in the same frequency channel. Each message is independent, spread spectrally with a unique code and the data stream contains a subset of all known codes. The apparatus finds a specific code and a constant phase shift between the incoming code and a reference code by serially moving the data stream through a shift register (40), subjecting all the shift register outputs to a single expected reference code and accumulating the result for each output using a plurality of accumulators (42). The code and phase shift is indicated by the largest magnitude of the accumulation, above a threshold, generated by circuit (48), corresponding to the shift register output for the correct phase shift betwen the incomming code and the reference. When an integration cycle terminates, the time shift delay increases by the length of the shift register (40). The process continues for all possible relative time shifts and all the reference codes.