availability, landline connections, and functions for each operator position. The switch
also supports remotely located configuration terminals and operator positions.
Operator position equipment is linked to the switch. Operators select and switch
communications channels by using touch entry devices (TED) or hard key panels.
Two jacks at each position accommodate a headset or handset for both a trainee and
instructor. The instructor uses the instructor jack to listen to the trainee's incoming and
outgoing radio, telephone, and intercom audio. The instructor can also override the
trainee; however, the trainee will still hear the instructor s communications.
A TED is an interface device with a resistive touch-sensitive membrane (see Figure 5-
2). The user selects pages by touching the membrane. Each page displays a matrix of
selector keys pre-programmed for specific functions. One set of pages is used for radio
communications control and another for telephone and intercom communications
control. The touch keys display icons and color bars to provide key status indications.
The color bars flash at different cadences to indicate the operational status of each