Single port FXO/FXS telephone fibre converter, singlemode, multimode or CWDM


  • POTS (Plain Old Telephone System) over fibre converter/extender
  • Extend telephone voice transmission up to 120km over fibre
  • Network management via terminal, web or SNMP in FRM220 (NMC)
  • Supports caller ID Pass-Through
  • Selectable FXO or FXS mode
  • Supports FXS to FXS hot line
  • Not for use with FAX or Modems


The FRM220-FXO/FXS is a POTS (Plain Old Telephone System) over fiber converter/extender. The POTS connection uses a standard RJ-11C modular connector for one copper pair connection. A pair of FRM220-FXO/FXS is required to implement an end to end system. FXO mode connects to a telephone line (PSTN) or PBX station line and has ability to detect ringing voltages and to act as a telephone. FXS mode is the reciprocal unit and has ability to act as PSTN and connects to a telephone device.

POTS voice over fibre with hotline feature


Item Description
Optical Interface

Connector SFP-LC / 1x9 (SC, ST, FC)
Fibre MM 62.2/125μm, 50/125μm, SM 9/125μm
Rate: 51.84Mbps
Distance MM 2km, SM 15/30/50km, WDM 20/40km
Wavelength MM 1310nm, SM 1310, 1550nm
WDM 1310Tx/1550Rx (type A) 1550Tx/1310Rx (type B)

Electrical Interface

Connector RJ-11
FXO mode Impedance : 600 ohms
Coding : 16 bits liner
Loop Current : 10~100mA
Ring Frequency : Acceptable 20 ~50Hz
Insertion Loss: 0.0 ± 1.0dB at 1000Hz
Level Gain : TX 0dB, RX -3dB
FXS mode Coding : 16 bits liner
Dial: DTMF and Dial Pulse
Battery Source: 48VDC ± 4V
Ringing Waveform : Sine wave
Impedance : 600 ohms
Ringing Frequency :
20/25/30/35/40/45/50/55 Hz selectable
Ring Cadence: FXS to FXS : On / 1 sec, Off / 2 sec
FXO to FXS; Reproduces the cadence detected by FXO
Insertion Loss 0.0 ± 1.0dB at 1000Hz
REN: 4.0B(Ring Equivalence Number)
Level Gain : TX 0dB, RX -3dB


LED (Power, FX Link, Phone Act, Test)

Power Input


Power Consumption

< 6W


Card: 155 x 20.8 x 88mm (D x W x H)




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


10 ~ 90% non-condensing




65,000 hrs

Ordering Information

Order Code Description
CT-FRM220-FXO/FXS-ST002 FXO / FXS fibre converter card ST, 2Km, 1310nm, 11dB
CT-FRM220-FXO/FXS-SC002 FXO / FXS fibre converter card SC, 2Km, 1310nm, 11dB
CT-FRM220-FXO/FXS-FC002 FXO / FXS fibre converter card FC, 2Km, 1310nm, 11dB
CT-FRM220-FXO/FXS-ST015 FXO / FXS fibre converter card ST, 15Km, 1310nm, 12dB
CT-FRM220-FXO/FXS-SC015 FXO / FXS fibre converter card SC, 15Km, 1310nm, 12dB
CT-FRM220-FXO/FXS-SC015 FXO / FXS fibre converter card FC, 15Km, 1310nm, 12dB
CT-FRM220-FXO/FXS-ST030 FXO / FXS fibre converter card ST, 30Km, 1310nm, 20dB
CT-FRM220-FXO/FXS-SC030 FXO / FXS fibre converter card SC, 30Km, 1310nm, 20dB
CT-FRM220-FXO/FXS-FC030 FXO / FXS fibre converter card FC, 30Km, 1310nm, 20dB
CT-FRM220-FXO/FXS-SFP Single port FXO/FXS fibre converter, Optional SFP (Model : SFS-50xx-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