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GENERAL DESCRIPTION
The FLD2SA has four fiber optic ports:
two emitters and two detectors. This
allows a standard daisy chain
configuration with two fiber optic
cables running between each modem.
Since the signal is regenerated at each
modem there is no physical limitation
on the amount of remote intersections
that can be tied on a fiber network.
The main communications port, DB9F,
is switch settable for either RS-232 or
RS-485. The mode is indicated on the
rear panel by LEDs.
The FLD2SA is configured at the factory
for either 850nm Multi-Mode operation
or 1310nm Single-Mode operation.
Both versions can operate at 1200bps
to 115kbps.
The standard versions of the FLD2SA
are equipped with battery backup. The
rechargeable NiMH Batteries that can
power the FLD2SA for 6 hours after
power loss. This will maintain
communications through an
intersection that has lost power.
The Anti-Streaming function prevents a
single controller from continuously
transmitting. The Anti-Streaming time
can be adjusted using the rotary switch
(S1) located at the rear of the modem.
Rotate S1 to “0” to deactivate Anti-
Streaming.
Anti-Streaming is automatically reset
when the controller stops transmitting.
However, the Anti-Streaming LED will
remain on until the reset button (S3) is
pushed.
This allows the technician to see if a
controller ever had a problem and
allows the controller to operate
normally if the problem clears itself.
The NiMH batteries are assembled in a
DC power pack on the PC Board and
are easily replaceable. The charge
current and voltage are continuously
monitored to prevent overcharging and
over-discharging the batteries.
To protect the batteries if the
temperature drops to 0°
°°
°C or less, the
charger is disabled.
When the battery is fully charged, a
trickle charger is activated and keeps it
fully charged at all times.
The status LED indicates whether the
full charger is on (solid red) or when
the trickle charger is on (Turning on
and off slowly).
The FLD2SA has the option of using the
presence of data coming from upstream
to control CTS. This will prevent data
collisions between two controllers. The
CTS signal will hold off transmission
from the attached controller until the
data from upstream has passed
through.
