SECTION б - INSTALLATION
TRANSMITTER SHARING
A number of considerations must be taken into account when more than one
paging terminal must share control of the transmitter. The most important
precaution is to ensure that the paging terminals never try to
simultaneously seize the transmitter. Each terminal can require two
inhibits - one from the receiver that indicates Channel Busy and one from
the other terminal that indicates that the transmitter is already being
used. The actual signal that shows this may be the PTT closure or a Request
to Transmit closure. The Model 16 has two separate inputs so that these
signals may be kept electrically isolated.
To prevent two paging terminals that are waiting to transmit from trying to
seize simultaneously after a Channel Busy signal disappears, the two
terminals can be programmed for different Channel Busy times.
The digital signals from the two paging terminals must be kept isolated. A
jumper "P3" is provided to isolate the digital data output when the Model
16 is idle or waiting for the transmitter. With P3 in position "B", the
digital data line is routed through SPST relay contacts which are operated
with the PTT relay. When idle, the "DIG DATA" output will be electrically
isolated. When the PTT relay is activated, the "DIG DATA" output will be
connected to the RS-232C compatible output circuit. With P3 in position
"A", the "DIG DATA" output will always be connected to the RS-232C
compatible output circuit.
Finally, the digital polarities and the data mode polarities for both
paging terminals must be matched to ensure that both paging terminals will
properly signal pagers.
6-5
