A method and apparatus are described establishing multimedia communications on
a shared communications channel. A first and a second communication unit, such
as a master and slave unit, establish a synchronous communications link. Additional
synchronous communications links may be established. A first data packet associated
with the synchronous communication link is communicated to the second communication
unit by including an address. Time slots reserved for the synchronous channel by
the first unit are separated by a fixed time interval. One or more additional communications
units may communicate over an asynchronous link established between the master
and additional units using remaining time slots. Data packets may be communicated
to additional units by including addresses associated with each additional units
The synchronous link may be interrupted with the asynchronous link by communicating
an asynchronous data packet on a time slot reserved for the synchronous communications
link. The asynchronous link may be a Time-Division duplex link for alternately
transmitting and receiving on different ones of the remaining time slots. Asynchronous
data packets communicated to additional units on remaining time slots. The master
unit may poll each additional units for a response packet to the asynchronous data
packet. On a Time-Division duplex link, additional units alternately receive the
poll from the first communication unit and transmit the response packet on different
ones of the remaining time slots.