The development of a differential phase-shift keying (DPSK), direct sequence, spread spectrum modem is conducted for the purpose of creating a prototype design to be implemented in a multi-user environment. In this design, a maximal length sequence of 31 chips is used to spread the information data. The multi-user performance analysis is performed by using Bit Error Rate (BER) test equipment (1645 Hewlett Packard data error analyzer). A multi-user interference cancellation circuit for two users is introduced, and measurements are performed to show its effectiveness. The design itself encompasses the selection of components and demonstrates that the preliminary operational characteristics of a spread spectrum DPSK modem scheme for CDMA application can be achieved.