4/8 E1/T1 + GbE Fibre Multiplexer



4/8 port E1 Fibre multiplexer with an additional Gigabit Ethernet trunk, plus order wire and clear channel RS- 232

  • 4/8 channels unframed E1/T1 + Gigabit Ethernet
  • Auto MDI/MDIX & Auto-Negotiation or Force Mode
  • Supports link fault Pass-Through for Ethernet
  • One clear channel RS232 up to 250Kbps(Async)
  • Loopback tests on E1/T1, RS232, fibre ports
  • Order wire Ear / Microphone port


The FRM220-GFOM04/GFOM08 is a 4/8 channel E1/T1 fibre multiplexer with an additional Gigabit Ethernet trunk, plus order wire and clear channel RS- 232, constructed as a two slot wide card for the FRM220 series.

Advanced Management

When the FRM220-GFOM04/GFOM08 card is placed in the FRM220 rack with NMC, the administrator can view the converter card's status, type, version, fibre link status and alarms. When used as a remote, fibre connected standalone card, it can also be managed through in-band management via the chassis NMC. The card can be configured to enable or disable ports, reset ports, and provide local or remote diagnostic loopbacks.

8 port E1 over Fibre multiplexor

1 + 1 Protection

The 1+1 redundant optical aggregate of this multiplexer employs industry standard pluggable optics (SFP) operating at 1.25Gbps data rates. The SFP modules can be chosen to support single-mode, multi-mode, single fibre bi-directional or Coarse and Dense Wave Division Multiplexing.




Item Description
E1/T1 ports

Framing Unframed (transparent)
Bit Rate E1:2.048 Mb/s , T1: 1.544Mb/s
Line Code E1:AMI/HDB3, T1: AMI/B8ZS
Line Impedance E1: Unbalanced 75 ohms (BNC)
E1: Balanced 120 ohms (RJ-45)
T1: Balanced 100 ohms (RJ-45)
Receiver sensitivity Short haul
“Pulse" Amplitude Nominal 2.37V+/-10% for 75 ohms
Nominal 3.00V+/-10% for 120 ohms
“Zero" Amplitude +/-0.3V
Internal Timing +/-30 ppm
Jitter Performance According to ITU-T G.823
Performance monitoring According to ITU-T G.821
Standards ITU-T G.703, G.704, G.706 and G.732
Interface Connectors RJ-45
Test Loops LLB (Local Loop Back)
NELB (Near End Loop Back)
RLB (Remote Loop Back)
RRLB (Request Remote Loop Back)


Connector SFP LC
Data Rate 1.25 Gbps


Interface Type 10/100/1000Base-T
Connector RJ-45
Standards IEEE 802.3, 802.3u, 802.3ab
Duplex modes full/half


FX1 Link, FX2 link, E1/T1 Mode/Link/Loopback test, Order wire phone indicator, LAN Link/Speed.

Power Input


Power Consumption

< 12W


Card: 155 x 42.1 x 88mm (D x W x H)




0 ~ 50°C (Operating), -10 ~ 70°C (Storage)


10 ~ 90% RH (non-condensing)





Ordering Information

Order Code Description
CT-FRM220-GFOM04-SR 4 x E1/T1 RJ-45 and 10/100/1000Base-T Ethernet fibre optic multiplexer card (optional SFP module)
CT-FRM220-GFOM04-SB 4x E1 BNC and 10/100/1000Base-T Ethernet fibre optic multiplexer card (optional SFP module)
CT-FRM220-GFOM08-SR 8x E1/T1 RJ45 and 1000Mbps Ethernet fibre mux card with 4x2E1 RJ45 cable (optional SFP module, Model : SFS-70xx-xx)
CT-FRM220-GFOM08-SB 8x E1 BNC and 1000Mbps Ethernet fibre mux card with 4x2E1 BNC cable (optional SFP module, Model : SFS-70xx-xx)

More Information

Chassis and mounting options for the FRM220 family.

AC and DC power options available.  See individual products for further details.

1 Slot standalone chassis for ISDN, voice or data modules, AC or DC
1 Slot chassis with DB9 console port for Ethernet, voice or serial cards
2 Slot Ethernet, ISDN and serial chassis with console port
2 Slot chassis manageable via NMC card
4 slot Ethernet, ISDN and serial chassis, 1U
8 Slot multi service rack, 1U
20 Slot multi function chassis with Ethernet, serial and ISDN, 2u
20 Slot Ethernet aggregation rack, 2u
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