Dual OPX Interface Card (FXO Station and FXO CO side)

The OPX interface card is available in two variations:

  • The Quad card isolates up to four lines using a single fiber link.
  • The Dual card can isolate up to two lines using a single fiber link.

The CO side used an FXS interface card. It is powered from an express pair, or from a power source at the CO side (a jumper setting is required for this option). The card interfaces with the CO and provides an off-hook circuit, line polarity detection, ring detection, and battery disconnect detection.

The Station side uses an FXO interface card. This card is powered from the backplane supply of -48 Vdc. It provides battery feed with polarity reversal, ringing, and battery disconnect to the station side equipment.

Product Number CLEI Number Description Download Documents
720480MST, SSC   OPX interface card Specifications Installation Guide
720450MST, SSC   FXO interface card Specifications Installation Guide


  • Off premises loop start telephone
  • Off premises fax/modem up to 56.6 kb/s
  • Automatic ring down
  • Calling Number Delivery (CND) compatible
  • Calling Number Delivery on call Waiting (CNDW) compatible
  • Call waiting compatible
  • Open Switching Interval (OSI) compatible (brief battery disconnect)
  • Battery reversal compatible


  • Local powered
  • Available as a multi-mode or single-mode card
  • Available with SC or ST connectors