Abstract: A voice and data terminals networking system comprises a plurality of voice terminals capable of communicating with one another within an intercom system. Each voice terminal is designated with a unique first code and intercommunicated among an intercom system. The system includes a plurality of data terminals each is associated to a corresponding voice terminal and designated with a unique second code consisted by at least first and second numbers and is interconnected to a LAN system. A transition gateway selected from one of the voice and data terminals for interfacing between internal and external communications. The system further includes a device that is used for selecting the first and second codes of the voice and the associated data terminals; wherein the second number of the second code of the associated data terminal is selected by the means such that the second number of the second code is completely identical to the first code of the voice terminal.

Abstract: A local networking system, offers integrated communication services to multiple local voice stations and data terminals via a common transmission medium. This system, utilizing Frequency Division Multiplexing (FDM) signals as carrier, transports information with CSMA/CD protocol. Voice transmissions are organized in traditional TDMA format with fixed frame length and dynamically assigned time slots to avoid interference caused by other devices in the system. Data services operate in traditional CSMA/CD format, but restricted to specified blocks of time intervals. The voice service quality is guaranteed because the required channels and bandwidths, up to the designed maximum, are always available when needed. The grade of data service may be impacted by voice traffic volume which is automatically managed by data terminal's inherent design with CSMA/CD protocol. This unified digital multiplexing system is applicable to transmission media with restricted channels.