T3 DS3 E3 Fiber Optic Modem for T3 Extensions
for 10/100BaseT

When you need to tie building communications together at the T3 - DS3 level
the T3 DS3 Fiber Optic modems will let you extend out to 100KM.

T3 Fiber Optic Modem - FOM-T3

 Extends the range of 10/100BaseT signals over E3/T3 services via fiber optic cable up to 110 km (68 miles)
 Built-in bridge and VLAN support


T3 Fiber Optic Modem T3
 Wave Division Multiplexing (WDM) for transmission over single fiber link
 User-selectable IP multicast and broadcast prevention towards the WAN
 Multimode or single mode fiber


The FOM-E3/ETH and FOM-T3/ETH fiber optic modems convert a 10/100BaseT electrical signal into an optical signal with a range of up to 110 km (68 miles).

These modems transparently connect between LANs, achieving maximum bandwidth utilization of the E3/T3 link, without the heavy overhead associated with packet- or cell-based technologies. They provide built-in bridging and VLAN support at Ethernet/Fast Ethernet rates, enabling virtual connection of remote LANs (e.g., campus applications).

The Ethernet interface module performs frame filtering and forwarding at the Fast Ethernet maximum theoretical rate of 150,000 frames per second. The bridge causes no LAN delays.

Different optical interfaces are available:
- 850 nm for multimode fiber
- 1310 nm for single or multimode fiber
- 1310 nm and 1550 nm laser diode, long haul laser for extended range over single mode fiber
- WDM laser for transmission over a single fiber


The modems can be configured by the user  to enable or prevent broadcast and IP multicasting to the WAN as required. The FOM-E3/ETH and FOM-T3/ETH can be used to connect LANs and high speed routers over E3/T3 links to the network.

The products are available as standalone units. They can be mounted in a standard 19" rack using special hardware or two units can be mounted side-by-side.


The FOM-T3 is a T3 fiber optic modem that can extend a T3 circuit over fiber for extended distances.

  • Using 1550nm single mode the FOM-T3 has a maximum range of 68 miles
  • The FOM-T3 is transparent to T3 framing
  • It can operate over single mode or multimode fiber using 850nm LEDs, 1300 nm laser diode or 1550 nm laser diode
  • WDM option allows you to transmit and receive on a single strand of fiber for further fiber conservation
  • ITU standard compliant with G.703, G.921 and G.956
  • V.54 diagnostics for local and remote digital loopbacks
  • Relays major and minor alarms
  • Front panel LED indicators