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Fiber Optic Modem FOM8

Discontinued, recommended replacement is: FMUX/M-E1, FMUX/B-V

Optical Transceiver Parameters

Fiber Optic Modem FOM8 Features:
  • Multi mode, single mode or single-fiber fiber link up to 170 km
  • G.703 interface with data rate 2.048 Mbps
  • V.35/RS-530/RS-449/RS-232 interfaces wiith data rate up to 8.192 Mbps
  • Full duplex synchronous mode
  • Digital, remote and line loopbacks
  • Integrated BER tester
  • Dry contacts alarm interface
  • Stand-alone or rack-mount
  • AC or DC power
  • Certificate N OS/1-SP-911 of Russian Ministry of Communications

FOM8 is a high speed (up to 8 Mbps) Fiber Optic Modem with G.703 2048 kbps interface, framed in conformity with G.704/IKM-30 (E1) or unframed, or synchronous digital interface. The device supports point-to-point full duplex synchronous links with selectable data rates up to 8.192 Mbps at ranges longer then any copper modem can achieve (more then 100 km). The modem has two digital interface options: multi-standard interface and V.35 interface. The multi-standard interface has HDB44 female connector and supports RS-232, RS-530, RS-449 and V.35 standards. User has the flexibility to change the interface type by changing only the interface cable. V.35 interface has the standard M34 female connector.

FOM8 is available as a stand-alone unit or as a card for 19'' 3U Cronyx rack.

The modem can be equipped with different optical transceivers.


Data Rates on Digital Interface 64, 128, 256, 512, 1024, 2048, 4096 and 8192 kbps, Selected by Switch
Loopbacks Digital, Line, and Remote Loopbacks
G.703 Loopbacks Line Loopback, Remote Loopback
Dual Remote Loopback support Yes
Timing Sources INT (Oscillator), EXT (Digital IF), RCV (Optic Receiver)
Built-in BER Tester Yes
G.703 Interface
Data Transfer Rate 2048 kbps
Line Code HDB3
Line Impedance 120 Ohm (Twisted Pair) or 75 Ohm (Coax Cable), Selected by switch
Receive Signal Attenuation Range from 0 to 43 dB (up to 2.6 km of 22 AWG twisted-pair cable)
Jitter Attenuator in the receive path, 28UIpp attenuation
Error Detection Bipolar Violation
Alarm Interface
Connector Type 6 Pins Mini-DIN
Relay Contact Current up to 250 ma
Relay Contact Voltage up to 175 VDC

Optical transceiver parameters

Specification L15 L13X D13 D13S D85
Wavelength 1550 nm 1300 nm 1300 nm 1300 nm 850 nm
Fiber Type Single-mode Single-mode Single-mode Single-fiber, Single-mode Multimode
Light Source Laser Diode Laser Diode LED LED LED
Optical Output Power (avg) -3 dBm -3 dBm -19 dBm -17 dBm -20 dBm
Optical Power Monitoring (per G.956) Yes Yes No No No
Min. Receiver Input Power (10-10 BER) -39 dBm -39 dBm -38 dBm -36 dBm -39 dBm
Min. Cable Length Limitation No No No No No
Optic Cable Power Budget 34 dB 34 dB 17 dB 17 dB 18 dB
Max. Optic Cable Length (depends on optic cable) 85 - 170 km 56 - 85 km 28 - 42 km 28 - 42 km 3.5 - 5 km


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

PDF  FOM8 with interface V.35 / RS-530 / X.21 / RS-232 - User's Manual in Russian
PDF  FOM8 with interface G.703 (E1) - User's Manual in Russian
PDF Справочник по интерфейсным кабелям Cronyx.

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