Fom-8, Fom-6mp, Sync/async fiber optic modem – RAD Data comm 146 User Manual
Page 8: Async fiber optic multipoint modem

M I N I A T U R E F I B E R O P T I C M O D E M S
153
RAD Data Communications 2006 Catalog
12
M
INIA
TUR
E FIBER OPTIC M
ODE
M
S
FOM-8
FOM-8
Fiber optic cable
FOM-8
Sync/Async Fiber Optic Modem
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•
Selectable sync or async operation
•
V.54 diagnostics
•
Selectable data rates up to 19.2 kbps
•
Two versions: single mode and multimode
•
Range up to 15 km (9 miles) over single
mode fiber
•
Carrier-controlled for transfer of control signal
•
No external power required
•
Metal case
•
Card version
The FOM-8 is a sync/async fiber optic modem
operating full or half duplex over fiber optic cable. It
has a range of 15 km (9 miles) over single mode fiber
and operates at selectable data rates up to 19.2 kbps.
The FOM-8 has diagnostic capabilities
complying with the ITU V.54 standard.
Two loops are available: local analog loop
and remote digital loop. These are activated
by toggling pin 18 or 21 of the V.24/RS-232
interface.
In synchronous transmission, the transmit
timing can be selected for internal, external
or loopback clock. Asynchronous
transmission is converted internally to sync
format in compliance with the V.14
standard. Different async formats are
switch-selectable.
Innovative circuitry design allows operation
without external power, by drawing low
power from the DTE data and control
signals. The FOM-8 is packaged in a metal
case for reduction of EMI/RFI emissions.
The modem is available as a card for
mounting in a 19" rack (see CMN-16 nest,
card CMN-CF8).
FOM-6MP
Async Fiber Optic Multipoint Modem
RS-232
Host
Fiber optic
Remote terminal units
FOM-6MP/SL
FOM-6MP/DL
FOM-6MP/DL
FOM-6MP/DL
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•
Asynchronous transmission up to 38.4 kbps
•
Multidrop operation over a fiber link
•
Transmission range up to 46 km (28 miles)
over single mode fiber
•
RTS or data contention for multipoint
operation
•
Automatic disabling in the event of streaming
•
Variety of optical options, including:
multimode, single mode and laser diode
for extended range
The FOM-6MP async fiber optic modem operates over
fiber to connect remote terminals and computers,
connected in multidrop, to a central host. Transmission
range (regardless of the data rate):
• 3.5 km (2 miles) using 850 nm multimode fiber
• 30 km (18 miles) using 1310 nm single
mode fiber
• 46 km (28 miles) using 1310 nm laser
diode single mode fiber
The FOM-6MP contains two optical
interfaces and one V.24/RS-232 port. One
optical interface passes data to and from
the host while the other passes data to and
from the rest of the terminals in the chain.
The V.24/RS-232 interface is connected to
the local terminal.
Terminal contention for transmission to the
host is selectable: transmitting data or
raising RTS signal.
The FOM-6MP includes anti-streaming
protection which prevents blockage of data
transmission. The FOM-6MP disables a port
that blocks the polling for a preset, user-
selectable period of time.
LED indicators help the user to easily isolate
faulty segments along the chain of terminals.
The FOM-6MP requires an external DC
power supply of 10–30 VDC/500 mA.
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