Extend Analog Phone Lines Over Fiber – Line Powered​​

Fiber Optic Isolation Systems - 2 Wire POTS
2 Wire POTS

NEBS Level 3The 2 Wire POTS (Plain Old Telephone Service) system provides transmission of standard analog phone, telemetering, or PBX loop start signals over two optical fibers. The system transmits signals in the voice-frequency or audio range (300Hz~3500Hz) while providing ringing and off-hook detection. Common applications include telephone, faxes, and dial-up modems.

This fiber link card is NEBS Level III approved, is designed to be installed into any of the RLH Fiber Link Card Housings, and occupies a single card slot.

A complete system uses one CO and one Sub card.

Note: Special modifications are available for forward disconnect (SM07) and square wave ringing (SM10). Contact the factory for additional information.


  • Compatible with all 2 Wire POTS systems
  • CO side is loop powered
  • Available in Single and Multimode
  • Available with ST or SC Connectors
  • Convenient sub card LED status indicators
  • Compatible with a wide variety of Card Housings
  • Limited Lifetime Warranty
  • Made in USA

Transmission Method:
Frequency modulated light via two optical fibers

Multimode: 850nm
Singlemode: 1310nm
SM Long Haul: 1310nm

Fiber Type/Distance:
Multimode (62.5/125µm, 50/125µm): 1.5 miles/2.5km
Singlemode (9/125µm): 9 miles/15km; Long Haul 37 miles/60km

Fiber Connector Type:
ST or SC

7in. x 4in. x 1in. (177.8mm x 101.6mm x 25.4mm)
(Standard RLH Fiber Link Card Form Factor)

Operating Temperature:
-40˚F to +158˚F (-40˚C to +70˚C)

2 Wire POTS System
2 Wire POTS System


Lead Time: 1 to 2 Weeks*

For product questions, volume pricing and/or delivery outside of the US and Canada, please contact sales.


2 Wire POTS

Product configurationCard TypeModeConnectorDistanceFibersPart numberPricehf:att:pa_card-typehf:att:pa_modehf:att:pa_connectorhf:att:pa_distance
CO/FXO Card, Multimode, ST, 2.4km/1.5 miles, Dual FiberCO/FXO CardMultimodeST2.4km/1.5 milesDual Fiber8806-1234-03$680.00
SUB/FXS Card, Multimode, ST, 2.4km/1.5 miles, Dual FiberSUB/FXS CardMultimodeST2.4km/1.5 milesDual Fiber8806-1244-05$680.00
CO/FXO Card, Singlemode, ST, 15km/9 miles, Dual FiberCO/FXO CardSinglemodeST15km/9 milesDual Fiber8806-1261-01$830.00
SUB/FXS Card, Singlemode, ST, 15km/9 miles, Dual FiberSUB/FXS CardSinglemodeST15km/9 milesDual Fiber8806-1271-03$830.00
CO/FXO Card, Singlemode, SC, 15km/9 miles, Dual FiberCO/FXO CardSinglemodeSC15km/9 milesDual Fiber8805-1261-01$950.00
SUB/FXS Card, Singlemode, SC, 15km/9 miles, Dual FiberSUB/FXS CardSinglemodeSC15km/9 milesDual Fiber8805-1271-03$950.00
CO/FXO Card, Singlemode, ST, 60km/37 miles, Dual FiberCO/FXO CardSinglemodeST60km/37 milesDual Fiber8806-1261-01-LH$1,040.00
SUB/FXS Card, Singlemode, ST, 60km/37 miles, Dual FiberSUB/FXS CardSinglemodeST60km/37 milesDual Fiber8806-1271-03-LH$1,040.00
CO/FXO Card, Singlemode, SC, 60km/37 miles, Dual FiberCO/FXO CardSinglemodeSC60km/37 milesDual Fiber8805-1261-01-LH$1,160.00
SUB/FXS Card, Singlemode, SC, 60km/37 miles, Dual FiberSUB/FXS CardSinglemodeSC60km/37 milesDual Fiber8805-1271-03-LH$1,160.00
  • For the forward disconnect option, please note your part number, add -SM07 to the end, and get your quote here
  • For the square wave ringing option, please note your part number, add -SM10 to the end, and get your quote here
  • A complete system requires a FXO/CO card and a FXS/Sub Card

*Lead times are estimates and may vary. You will be contacted within 1 business day to go over the details of your order. If you require a specific date, let us know!
*Days = Business Days

WarningWarning: This product can expose you to chemicals including arsenic, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov.