The DDF is a passive equipment used to minimize high density of the cables for distribution and communication from/to digital terminal equipment.
All the transmission rate is based on 2Mbit/s.


The capability to handle large amounts of cables in a small footprint, it is one of the necessary facilities for digital transmission system because, at the same time, reduces the density of the links and provides significant cost-savings to the service provider.
In fixed networks the DDF system is installed between the user access (network interface) and transmission equipment (internal interface)

System Benefits

  • Fast and easy installation
  • High flexibility
  • High cable density
  • Wide range for all applications
  • High reliability
  • Meets all the requirements for 75/120 Ohm

DDF capabilities

  • 2 Mbit/s standard signal characteristics
  • 120 Ohm IN/OUT signals on transmission side (internal inter face)
  • 75 or 120 Ohm IN/OUT signals on user access side (network interface)
  • Two Meters maximum cable length supported for transmis sion between the Transmission Equipment and the DDF

DDF Product Portfolio

The DDF product portfolio provides different versions to meet a variety of cables and connectors on the network interface:

  • μCoax 1.0/2.3 (75 Ohm)
  • BNC (75 Ohm)
  • IDC (120 Ohm)
  • RJ45 (120 Ohm)
All the previous versions are available both in:
  • 16 x E1 (16 x 2 Mbit/s)
  • 21 x E1 (21 x 2 Mbit/s)

DDF Overview

  • The adaptation between the output of the card and the user connector is obtained by means of a E1/T1 transformer
  • Transformer with a “tap selection” on the prima ry coil; in this way two transformer ratio are avai lable to match the user impedance.
  • Characteristic impedance: 75 or 120 Ohm
  • Data rates: 2Mb/s
  • Jitter : no additional jitter is generated in the DDF
  • Return loss TX/RX : G.703 compliant

DDF Standard

The DDF has been designed according to the following standards:

  • Housing in standard 19” and ETSI rack(maximum height 1 U)
  • Environmental condition: ETSI EN 300 019
  • Electrical Interface: ITU-T G703
  • Mechanics: ETSI EN 300 119 CEI EN 60917 EC 60297
  • ECO Compatibility: European Directive 2002/95/EC
  • Safety: CEI EN 60950
  • EMI/EMC: ETSI EN300 386
DDF System Features
Mechanical Dimensions(mm) 44,45(H) x440(W) x120 (D)
Electrical interface ITU-T G703
IN/OUT Impedance@Network Interface Connector type
75 ohm 120 ohm μCoax 1.0/2.3 - BNC IDC - RJ45
IN/OUT Impedance@Internal Interface Connector type
120 Ohm (21 channels )
120 Ohm (16 channels )
2xRJ45 + 1xVHDCI
Operating temperature -40°C to +60°C
ROHS and WEE compliant Yes