Network Equipment & Antennas

Main Distribution Frames - Connection Tool

The Main Distribution Frame is the basic interface which provides an interconnection or a connection field between the subscriber lines and the exchange equipment. The MDF not only provides for connections between the subscriber and the exchange equipment, it also houses the protective equipment to protect the subscriber line and the expensive exchange equipment from over-currents and high voltage surges.

The MDF consists of a specially designed steel frame consisting of a number of individual parts assembled together to make a rigid structure. The individual parts are so designed that there is total interchangeability and ease of erection at site even by semi-skilled staff. The steel items are coated with a special hard-wearing material to protect them from atmospheric action. The wiring is made extremely simple and does not necessitate removal of the insulation, wrapping and soldering. The design of the connection elements and the unique tool provided to make the connections ensures a positive connection of the wire on the contact. The connecting elements and the protective equipment are modular in construction and totally interchangeable enabling easy installation and maintenance. Alteration of wiring to suit the day-to-day requirements is extremely simple.

Presently the MDF are available in four varieties :

128/256 MDF for small rural automatic exchange

512 port MDF for SBM exchange

1000 lines per vertical MDF

1600 lines per vertical (High density MDF)


  High Density MDF
Standard MDF
  1600 L/V-High Density MDF 128/256 MDF 512 P MDF 1000 L/V
Structure Powder coated steel structure Anodized Aluminum Powder coated steel structure Powder coated steel structure
Module Type Disconnection type Disconnection type Disconnection type Disconnection type
Connection By insulation displacement By insulation displacement By insulation displacement By insulation displacement
Access Front and back Front Front Front and back
Max. Capacity Modular in multiples of 1600L Upto 256 L Upto 512 L Modular in multiples of 1000L
Protection Thermister with GD tubes in IPM Thermister with GD tubes in IPM or only GD tubes in 10 line magazine Thermister with GD tubes in IPM or only GD tubes in 10 line magazine Thermister with GD tubes in IPM or only GD tubes in 10 line magazine
Earthling Copper earth bar magazines Copper earth bar Copper earth bar Copper earth bar
Earth Bar In-Built in to the modules External for IPM, Internat for Magazine External for IPM, Internat for Magazine External for IPM, Internat for Magazine
Mounting Floor Mounting in suites Wall Floor/Wall Floor Mounting in suites