FLD-496SA
3
A00474-1A
DESCRIPTION
The FLD-496SA is a combination of a
Fiber Optic Modem and a Type 496
Modem. The FLD-496SA has an FSK
input and output to the Fiber Optic
section of the Modem. This Modem will
tie directly to the FSK interface of our
type Model 496 Modems or other
compatible FSK Modem as is used on
NEMA traffic control equipment. The
existing Modems used in the traffic
control equipment can be left in place
when converting over to a Fiber Optic
system.
This means that you don't have to worry
about not having a standard EIA-232
interface available as with some NEMA
Controllers. Just leave the existing
Modems in place and connect the FLD-
496SA to the FSK lines from the existing
Modem. The FLD-496SA has a removable
Phoenix type terminal block on the rear
panel for easy connection.
The FLD-496SA operates at 9600 Baud.
The frequencies used by the host Modem
should correspond with a Mark Frequency
of 11200 Hz and a Space frequency of
17600 Hz to work correctly.
The FLD-496SA-1 operates at 850 nm
into Multi-mode cable using ST type
connectors. The FLD496SA-2 has 1300
nm single mode LED emitters and
detectors and is available with ST or FC
type connectors. The Fiber Optic section
of the FLD-496SA-1 has a range of about
3-5 Km depending on the connector loses
and quality of the cable. The range of the
FLD-496SA-2 depends on the power level
of the Emitter being used. Power ranges
of –21 to –13 dBm are available.
The FLD-496SA has two modes of
operation: as a Master and as a Remote.
In the Master Mode, data from the FSK
section is transmitted to both Emitters of
the Fiber Optic section. Data from the
two Detectors is ORed together and sent
to the FSK section.
In the Remote Mode of operation, data
coming in on Detector 1 is sent to the FSK
section and to Emitter 2 where the signal
is regenerated and sent on to the next
Remote Modem. Data coming upstream
from a Remote Modem comes in on
Detector 2 and is ORed with data from the
FSK section and is transmitted out
Emitter 1. The Fiber Optic signal is
therefore regenerated. There is no
maximum length for a system as long as
each hop is less than the maximum range
of the FLD-496SA being used.
A 9-Volt Lithium battery is used to keep
the Fiber Optic section running in the
event of a power Failure. A front panel
Led indicates that the battery is good
when lit and needs to be replaced when
dark. A front panel switch allows you to
disconnect the battery to prevent it from
discharging when the Modem is not being
used.
The FLD-496SA is normally operated 4
wire full duplex but can also be operated
in a 2 wire half duplex mode by setting
the appropriate switches on the rear
panel. The Local Echo switch is normally
off for full duplex and on for half duplex.
The FLD-496SA also has anti-streaming
capability that can be turned on and off
with a dipswitch on the rear panel. Anti-
streaming prevents a controller from
