HDSL2 Plug-in Isolator Card

The 2-wire HDSL2 isolator plug-in card (Models 751340R2 and 751340SP) provides high voltage isolation for an HDSL2 circuit terminating in an H2TU-R located inside the substation

Product Number CLEI Code Description Download Documents
751340R2 SLC5EBAAAA HDSL2 Plug-in Isolator Card Specifications Installation Guide
751340SP NPP1EWABAA HDSL2 Plug-in Isolator Card with
Span-power capability
Specifications Installation Guide


  • HDSL2 with support of -129 Vdc & -190 Vdc on the loop
  • Data transmission lines within the passband of the card
  • Station side span-powered H2TU-R (751340SP only)
  • Station side locally powered H2TU-R (751340R2 or 751340SP)


  • Provides isolation of 50 kV rms (70 kV peak) while maintaining full communications across the air gap by an isolation transformer that provides low-loss, low-distortion transmission between terminals.
  • Card Model 751340R2 is passive and does not require power to operate. A locally powered H2TU-R must be used on the Station side.
  • Card Model 751340SP requires a -48 Vdc input and will provide 125Vdc Span Power on the Station-Side of the isolator to power the HDSL2 terminating unit, H2TU-R.
  • The Teleline Isolator shelf power can be maintained during the installation of the cards.
  • The CO-side of the 751340SP and 751340R2 enables the return of loop sealing current or span power. DC is not transfered from the CO-side to the Station-side. DC Span Power is regenerated on the Station-side, if so configured.

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


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