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Fiber Optic Modem FOM8-E3

Discontinued, recommended replacement is: Nothing

Using of the device
Optical Transceiver Parameters

Fiber Optic Modem FOM8-E3 Features:
  • E3 stream (G.703, 34368 kbps) transmittion, both framed and unframed modes
  • Single-mode or multimode fiber, single fiber available, distance up to 150 km
  • ITU-T (CCITT) G.703, G.751, G.823 and G.955 standards conformance
  • Local and remote fiber optic line loopback
  • Local E3 port loopback
  • E3 monitor mode
  • Integrated BER tester
  • RS-232 control console port
  • Remote SNMP control using separate Ethernet port
  • Dry contacts alarm interface
  • Construction: standalone or 1U rack mount for 19'' cabinet
  • AC or DC power supply
  • Certificate N OS/1-SP-911 of Russian Ministry of Communications

The FOM8-E3 device is a high speed fiber optic modem for E3 (34368 kbps) digital data stream transmittion. It covers point-to-point full duplex synchronous data links for distances longer then any copper modem can support (up to 150 km). Use of the devices is also suitable for short distances in case of strong electromagnetic fields environment.

FOM8-E3 is available as a standalone unit or as a 1U rack mount box for 19'' cabinet.

The modem can be equipped with different optical transceivers.

Currently available models are listed in Prices. Please, contact technical support if you are unsure which model to choose.

Using of the device

Typical scheme of using of the device

Typical scheme of using of the device

The device may be controlled by both ASCII terminal (console) connected to RS-232 port and by SNMP using Ethernet connection.

There are two modes of operation: Unframed and Framed.

If in Unframed mode then full bandwidth is used for data transfer in transparent mode.

If E3 stream is framed and NAT bit of the E3 frame is not used by the equipment connected to E3 ports then both local and remote devices may be configured for Framed mode operation. This way virtual monitoring channel will be establish between devices allowing to control remote device and monitor its state from the local console terminal.


E3 interface
Connectors type BNC
Line code HDB3
Error Detection Bipolar violation
Line impedance 75 Ohm (coax cable)
Receive signal attenuation range from 0 to -15 dB
Max cable length 400 m
Overvoltage protection Sidactors
Overcurrent protection Fuse
Alarm interface
Connector type DB-9 (female)
Relay contact current up to 600 mA
Relay contact voltage up to 110 VDC or up to 125 VAC
Console port
Interface type, connector type RS-232 DCE, DB-9 (female)
Data transfer mode Asyncronous, 9600 bps, 8 bit per character, 1 stop bit, no parity
Modem signals DTR, DSR, CTS, RTS, CD
SNMP port
Interface type Ethernet 10Base-T
Connector type RJ-45
Diagnostic modes
Loopbacks Local on E3 port, local and remote on fiber optic link
BER tester Built-in
Control From local console (control RS-232 port), from console of remote device, by SNMP
Phisical dimensions and weight
Standalone box 210 мм x 260 мм x 70 мм; 1,3 кг
1U box for 19'' rack mount 444 mm x 262 mm x 44 mm; 3,4 kg
Power supply
AC 176 to 264 V, 50 Hz
DC 36 to 72 V
Max power consumption 12.5 Wt
Environmental requirements
Temperature range 0 to 50 oС
Relative humidity Up to 80 %, no condensation

Optical Transceiver Parameters

Specification TM13 TS13 TS15 TW13 TW15 DW13 DW15
Fiber Type Multimode
Single Mode
Single Mode
Single Mode
Single Mode
Single Mode
Single Mode
No. of Fibers Two Two Two One One Two Two
Minimum Fiber Optic Cable Power Budget 13 dB 29 dB 29 dB 26 dB 26 dB 17 dB 17 dB
Fiber Optic Cable Minimum Length Limitation No No No No No No No
Maximum Fiber Optic Cable Length (depends on cable parameters) 2 - 5 km 40 - 80 km 80 - 150 km 40 - 60 km 40 - 60 km 25 - 40 km 25 - 40 km
Note Uses WDM, requires TW15 optical module at opposite end Uses WDM, requires TW13 optical module at opposite end Uses WDM, requires DW15 optical module at opposite end Uses WDM, requires DW13 optical module at opposite end
Wavelength 1310 nm 1310 nm 1550 nm 1310 nm 1550 nm 1310 nm 1550 nm
Optical Output Power -19 dBm -5 dBm -5 dBm -8 dBm -8 dBm -14 dBm -14 dBm
Spectral width 200 nm 3 nm 1 nm 3 nm 1 nm 4 nm 2 nm
Maximum Input Optical Power -14 dBm -3 dBm -3 dBm -3 dBm -3 dBm 0 dBm 0 dBm
Receiver Sensitivity -32 dBm -34 dBm -34 dBm -34 dBm -34 dBm -31 dBm -31 dBm


Some of the documents are in Adobe® Acrobat® Reader® format

PDF  Optical modem FOM8-E3 - Installation and Operating Manual (in English)
PDF  Optical modem FOM8-E3 - Installation and Operating Manual (in Russian)
MIB  MIB-files for SNMP-management

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