An interconnect communication system is provided that provides for
dispatch-type services including Instant Access call set up, talkgroup
creation and management, and in-band floor arbitration and mode switching
that employ in-band signaling tones. By providing talkgroup creation and
management and in-band floor arbitration that are transparent to the
underlying network, the talkgroup creation and management and in-band
floor arbitration may be implemented in a legacy system without the need
to modify the network and regardless of the type of network employed.
Furthermore, by providing Instant Access call set up procedures and mode
switching procedures that are capable of utilizing modified versions of
known messages, the procedures may be implemented in a legacy system in a
simplified manner, minimizing the impact of an addition of such
procedures to a legacy network.