G703/FE1: G.703 (E1) Converter for framed and unframed Transmission


The G.703 FE1 Access Units are single port access units for Unframed E1 or Fractional E1 services. Data Port rates are selectable via DIP-switches, for any multiple of 64Kbps up to 2048kbps. User data is placed into the E1 frame, using only the required number of timeslots. Timeslot assignment is accomplished according to the Data Port speed and may be randomly selected by DIP-switches.

The main E1 link may be clocked from the recovered receive clock (LBT), from the data port, or from an internal oscillator. The data channel interface is RS-530 standard. Adapter cables are available for V.35, X.21 and RS-449. The G.703 FE1 DIP and slide switches, located on the side and front panels, provide for easy setup and control of all functions.


  • LTU (Line Terminating Unit) built in unit.
  • Single port access to Unframed and Fractional E1 services.
  • Interface conversion between G.703 and RS-530, RS-449 (V.36), X.21 or V.35.
  • Data rate: DIP selectable sync Nx64Kbps to 2048Kbps.
  • Fully transparent signal conversion.
  • Clock Regeneration from incoming HDB3 data.
  • Diagnostic Loopbacks both for G.703 and Data Port sides.
  • All ones monitor.
  • Decoded data in NRZ form.


G.703 Specifications

  • Type Bidirectional (E1) 2048kbps.
  • Line 4wire, 26-16AWG.
  • Range Up to 1500 meter, 24AWG or better.
  • Impedance RJ-45/48 120 ohm (balanced). BNC 75 ohm (unbalanced).
  • Pulse amplitude 2.37V nominal for BNC, 75 ohm. 3.00V nominal for RJ-45/48, 120 ohm.
  • Zero amplitude ±0.1V max.
  • Clock freq. 2.048 MHz.
  • Freq. Tracking ±50ppm.
  • Jitter Complies with ITU-T G.823
  • Connector RJ-45/48 or BNC.
  • Complies with ITU G.703, G.704, G.706 and G.823.
  • Frame format CAS/CCS,Unframe/Frame.
  • CRC check CRC-4 enable/ disable.
  • Line code HDB3.

Data Port Specifications

  • Type RS-530/DB25 Standard or V.35, RS-449(V.36) or X.21 with adapter cable.
  • Data rate 64kbps to 2.048Mbps.
  • Connector DB25/F with adapter cable.
  • Line code NRZ

General Specifications

  • Power: AC 110/230V 50/60Hz adapter to DC 9V
  • Temp. range: 0 C to 50 C
  • Humidity: 10% to 90% relative humidity, non-condensing.
  • Dimensions: 19.2cm (L) x 10cm (W) x 2.4cm (H)
  • Weight: 400g net
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