Single 2W/4W AC Data Interface Card

The Single 2W/4W Interface Card isolates a single two-wire or a single four-wire AC data line using a fiber link. The interface card is provided in two variations:

  • The CO side card can be powered from the line sealing current: loop sealing when operated in 2W mode, or simplex sealing when operated in 4W mode
  • If line sealing current is not provided by the CO equipment, the card can be powered locally through the shelf’s supply of -48 Vdc. When line powered, the card will operate with sealing currents as low as 7 mA
  • The card will not reproduce the loop or sealing current on the Station side
  • The Station side card can only be powered locally, and the power source provides no more than -48 Vdc
Product Number CLEI Number Description Download Documents
720460MST, SSC SLL7AAJCAA Single 2W/4W AC Data Interface Card Specifications Installation Guide
720470MST, SSC SLL7AAKCAA Single 2W/4W AC Data Interface Card Specifications Installation Guide


  • Voice band or any modem compatible up to 56 kbps
  • Dedicated line modems
  • Supervisory control and data acquisition (SCADA) systems
  • Tone relay control systems
  • Analog carrier systems
  • Any other equipment using tone related signalling


The Single 2W/4W card uses a type of encoding on the fiber that reduces power consumption to a minimum, while still being able to transmit over 2km (1.2 miles) of multi-mode fiber and 16km (9.9 miles) of single-mode fiber.

  • Station -48 Vdc Multi-mode ST Connector - Local Powered 720460MST
  • Station -48 Vdc Single-mode SC Connector - Local Powered 720460SSC
  • Central Office -48 Vdc Multi-mode ST Connector - Line Powered 720470MST
  • Central Office -48 Vdc Single-mode SC Connector - Line Powered 720470SSC