14
Loop-Through
Mode
In the loop-through mode, the output of the stereo generator is
cabled directly to the
PILOT OR MPX INPUT
of the Model 712 as
shown in Figure 4, below. Connect the
RDS OR MPX OUTPUT
of the
encoder to a composite/MPX wideband input of the FM exciter.
When internally jumpered for loop-through operation, the
composite/MPX signal
passes through
the encoder with unity gain,
and with the RDS subcarrier added.
Figure 4 -
Loop-Through Encoder Connection
Manually
Activating
the TA Flag
The Travel Announcement feature is a temporary command. This
flag
must
coincide with the actual voice warning of a traffic
condition. The encoder includes a provision to access this flag with
a manual switch closure, which will doubtless prove faster, more
convenient and more reliable than software control of the TA
function.
A run of single-conductor shielded cable may be taken from the
TA
CONTROL
BNC connector on the rear panel of the encoder to a
normally open
momentary
(spring-return!) pushbutton switch
located conveniently at the announcer s operating position.
The TA flag will be transmitted as long as the switch is held down.
It is important that this alert is active only for the duration of a
traffic announcement.
The TA flag must be
turned off
immediately
after completing the verbal traffic warning.
DATA INTERCONNECTION
The rear-panel
RS232 SERIAL DATA INTERCONNECT
DB-9 port is
addressed in simple ASCII text for programming the various static
FM STEREO GENERATOR
PROGRAM
LINE IN
MPX OUT
MODEL 712 ENCODER
LOCAL TA RS-232 PILOT OR MPX RDS OR MPX
CONTROL LINK INPUT OUTPUT
FM EXCITER
1 2 3
WIDEBAND INPUTS
RF OUTPUT
