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Optical Scientific Inc
OFS 2000FW User’s Guide
P/N 1910-901-1
Rev. 03/28/13
30
3.13.2 Fiber Optic Modem (FOM) Connections
The FOM option is available for installations where the Control Box must be connected via a fiber to the user’s
computer. The FOM converts the RS-232 levels to light pulses for noise free, long distance transmission.
Using two multi-mode fibers (62.5/125), the FOM will transmit over 1 mile at 28.8 kbps.
FOMs are used in pairs, one DB-25 male connector is plugged in J2 on the Control Box and one at the remote
computer. Since OFS is configured as a DCE device and the user’s computer is configured as DTE, the FOM
at the OFS side should be configured as DTE and the FOM at the user’s computer side should be configured
as DCE for proper data communication. The user must supply dual multi-mode 62/152 fibers with ST type
connectors to connect between the FOMs. As shown in Figure 3.28, the fibers are installed in a crossed
pattern with the TX (Out) of one FOM connecting to the RX (In) of the other FOM.
Figure 3.28 Fiber Optic Modem Connection
FOM AT USER
COMPUTER
J2 / FOM
USER SUPPLIED
62/125 DUAL
MULTIMODE FIBER
CABLE