Universal HDSL Plug-in Isolator Card

The Universal HDSL cards (Models 751339R2 and 751339SP) provide high voltage isolation for:

  • one or two HDSL2 circuits terminating in an H2TU-R located inside the substation
  • one HDSL or HDSL4 circuit terminating in an HTU-R or H4TU-R located inside the substation
  • on-board jumpers allow you to configure the plug-in isolator card for 2-wire or 4-wire operation.

Product Number CLEI Code Description Download Documents
751339R2 SLC5DBAAAA Universal HDSL Plug-in Isolator Card Specifications Installation Guide
751339SP NPP1GW0BAA Universal HDSL Plug-in Isolator Card with Span-power capability Specifications Installation Guide


  • HDSL Classic (2B1Q), HDSL2, dual HDSL2, and HDSL4 with support of 129 Vdc & 190 Vdc on the loop
  • Data transmission lines within the passband of the card
  • Station side span-powered HxTU-R (751339SP only)
  • Station side locally powered HxTU-R (751339SP or 751339R2)


  • Isolation of 50 kVrms (70 kV peak) while maintaining full communication between terminals
  • Communication maintained across the gap by isolation transformers that provide low-loss low-distortion transmission
  • Card Model 751339R2 requires that a locally powered HxTU-R be used on the Station side.
  • Depending on jumper positions, card Model 751339SP enables the use of both a locally-powered or span-powered HxTU-R.
  • Jumper settings allow you to configure either card to provide for simplex sealing current (for HDSL or HDSL4) or loop sealing current (for HDSL2) on the CO side. The current will not be transferred to the Station side.
  • The Teleline shelf power can be maintained during the installation of the cards

The card can be housed in the 3-card shelf, the 5-card shelf, the 8-card shelf, or in any of our High Voltage Interface (HVI) pre-configured units.


Keyword Internal Search

Type the name or product number