Method and system for processing telephone calls involving two digital wireless subscriber units that avoid double vocoding

A method and system determines whether the receiving subscriber unit is also part of a digital wireless telephone system that has compatible vocoding capability. If so, vocoded data is converted into tones that are introduced into a wire-based telephone system for routing to the appropriate receiving digital wireless telephone system. When these tones are received by the receiving digital wireless telephone system, the vocoded data is regenerated based on the tones and then transmitted to the receiving subscriber unit. If the originating and receiving wireless subscriber units are part of the same digital wireless telephone system, the steps of conversion to tones and introduction into the wire-based telephone system may be omitted, and the vocoded data is passed between the two digital wireless telephone systems via an all-digital connection such as an ATM packet network or a wire-based telephone connection where the integrity of digital information is assured.