RAD VSC, VSC-X Voice Interface Converters

Call us for Pre-sales and discount pricing

  301-924-7400 Support

RAD VSC, VSC-X Voice Interface Converters


  • VSC is a voice and signaling converter, enabling connection of voice equipment to data communications equipment. VSC converts the 2-wire/4-wire interface of the data equipment to the FXS interface of a telephone set, enabling direct connection of a telephone set to the voice interface of a time division multiplexer.
  • VSC is available as either a stand-alone unit (VSC) or as a rack-mount card (VSC/R).
  • VSC provides FXS loop start or ground start. The VSC/R provides FXS loop start only.
  • VSC and VSC/R recognize the telephone pulses for on-hook, off-hook and dialing, translate the pulses into the proper signaling standard, and send the resulting signal over the "M" lead. When detecting activity on the "E" lead, VSC sends the ringing signal to the telephone and the ring back tone to the other side.
  • The voice interface on the E&M side is switch-selectable for either 2-wire or 4-wire operation. The voice level to and from the telephone can be adjusted by means of a gain control in the range of +9 dB to -9 dB. (Gain control is not supported in the VSC/R.)
  • The ring signal towards the telephone is modulated for approximately one second on, three seconds off, to simulate PABX operation.
  • VSC has internal protection on the E&M lead to avoid damage in the event of improper operation.
  • The VSC/R cards fit into the VSC-MN 19" card cage. The card cage includes a power supply and can carry up to 12 VSC/R cards in the AC option, or up to 14 cards in the DC option. The VSC/R cards can be mixed with the VSC-X/R (FXO) cards.


  • Converts standard telephone set interface (FXS) to E&M interface
  • Loop start / ground start telephone types
  • 4-wire or 2-wire E&M interface
  • Compatible with EIA RS-464 Types I, II and III, British Telecom SSDC5
  • Selectable gain control
  • Suitable for dial and touch-tone (DTMF) telephones
  • Stand-alone unit (VSC) or rack-mount card (VSC/R)

Voice and Signaling Converter,
stand-alone unit with internal power supply

Voice Signaling Converter, card for VSC-MN 19" card cage

19" card cage for up to 12/14 VSC/R cards. Power supply included

* Specify power supply:
230 for 230 VAC
115 for 115 VAC
100 for 100 VAC
48 for -48 VDC




RAD Products

For discount pricing on RAD Data Communications
email us at sales@data-connect.com
or call 301-924-7400