Model 922-FOM


The Model 922-FOM is a lightly managed Ethernet switch designed and tested for use in subsea controls and communication applications. With five copper Ethernet ports and two optical Ethernet ports, the FOM may be operated with both optical ports and (optionally) one copper port configured for redundant operation, so that the failure of one link automatically and rapidly redirects traffic to one of the other ports in a protocol independent manner.

Communication formats include SIIS Level 3 Ethernet at 10 Mb/s or 100 Mb/s with ports configured manually or through autonegotiation. Optical links operate in 100Base-FX format (100 Mb/s). A range of subsea-qualified, pluggable, fiber-optic transceivers enables many optical topologies, including dual fiber operation and bidirectional operation with up to 16 wavelengths on a single fiber using CWDM (Coarse Wavelength Division Multiplexing) technology. Fiber umbilicals of up to 200 km length are supported.

Model 922 software provides advanced diagnostics via Modbus TCP for real-time health monitoring of the system as well as easy configuration of all interfaces and modes of operation.


  • User configurable, 7-port Ethernet switch, 10/100M
  • Dual optical transceivers for redundant 100M Ethernet uplink with automatic failover
  • Isolated, fault-tolerant power and signal interfaces
  • Qualified per ISO 13628-6 and API 17F to Q1 levels
  • Advanced diagnostics and setup via Modbus TCP or Telnet
  • Proven hi-rel components rated for -40°C to +85°C
  • Robust remote update method for subsea firmware with multistage validation and permanent factory fallback code
  • UDP heartbeat packet with IP settings and key diagnostics
  • 3U Eurocard size for card rack or bolt-down installation


  • Reduces overall system costs and size
  • Delivers high performance optimized for subsea controls
  • Saves costs for qualifications and obsolescence management; avoids requalification of industrial solutions
  • Provides an easy upgrade path via remote code updates to "future proof" system designs
  • Supports many copper and optical configurations
922-FOM Specifications
Ethernet Interface (SIIS Level 3)
No. Ports 5 x Copper (4 on DIN connector, 1 on front)
2 x Optical (via SFP cages)
Protocols 10/100Base-T(X), copper
100Base-FX, optical
Protection ESD and transient suppressors (TVS)
500 Vrms isolation
Ethernet Switch
Layer 2 Functions
Includes broadcast storm protection, rate limiting, flow control, 802.1q VLAN, 802.1p port priority, port mirroring, fast aging
IP Configuration
DHCP with configurable static IP fallback
Diagnostics and Control
Modbus TCP, Webserver, Telnet
Diagnostics and Control Parameters Includes temperature, humidity, voltage, current draw, optical power (Tx/Rx), on time and power off events, Ethernet port status/configuration, MIB counters, card mftr. data (s/n, p/n, F/W revision)
Automatic link failover (fiber, copper)
1310 nm and 1550 nm standard
CWDM wavelengths (e.g. 1471 to 1611 nm)
Optical Power Budget
20 to 45 dB, depending on SFP installed
Cable Length
10 to 200 km, depending on SFP installed
Bidirectional (single fiber) transceivers
1See Subsea Qualified SFP Modules datasheet for available optical transceivers
Rear Card Edge
1 x 96-pin DIN 41612 (Ethernet, power)
Front Card Edge
2 x SFP (Ethernet, optical), single or dual LC
1 x 9-pin Micro-D (Ethernet)
37-pin Micro-D (replaces 96-pin DIN)
5 W typical (8 W max.)
Operating Voltage
+20 to +28 VDC, regulated input
Rated Current
0.4 A max.
ESD, EMI, over-voltage, reverse voltage, overcurrent (no fuses), 500 Vrms isolation
3U Eurocard, 4 HP, 160 mm x 100 mm
3U Eurocard rack or M2.5 hardware
Front panel, LED panel, heat plate
Design Life
> 20 years @ +40°C
> 250,000 hrs @ +40°C
Factory Acceptance Test (FAT)
At Tmin and Tmax design temperatures
ISO 13628-6, API 17F (Q1 Levels)
Includes 30 g shock, 5 g vibration
Firmware Update
Failsafe remote firmware update
Environmental Stress Screening (ESS)
Custom qualifications per OEM specification
Temperature -18°C to +70°C (design and operation)
-40°C to +85°C (storage)
5% to 85% RH, non-condensing

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Typical Applications

  • Subsea communications for drilling and production controls
  • Subsea Electronics Modules (SEM) and other subsea nodes
  • Upgrades to existing subsea systems and sensor hubs
  • Highly reliable industrial networking