Browse Prior Art Database

Automatic Network Impedance Switching

IP.com Disclosure Number: IPCOM000115929D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 64K

Publishing Venue

IBM

Related People

Benayoun, A: AUTHOR [+3]

Abstract

A communication adapter is attached to the network through a cable. Depending on the country this cable is either a 120 ohm twisted pair or a 75 ohm coax. The adapter has to internally provide the impedance accordingly.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 79% of the total text.

Automatic Network Impedance Switching

      A communication adapter is attached to the network through a
cable.  Depending on the country this cable is either a 120 ohm
twisted pair or a 75 ohm coax.  The adapter has to internally provide
the impedance accordingly.

The advantages of the current solution are the following:
  o  The network impedance switching is automatically performed when
      the network attachment cable is connected to the adapter
  o  The adapter P/N is unique whatever the country

Applications of the invention:
  o  This invention is applicable to any communication adapters to be
      connected to networks using different types of cable
  o  Example of communication adapters: Primary ISDN, E1 ....

      A communication adapter has a hardware network interface as
shown in Fig. 1.

The adapter connector is defined by the designer and receives the
appropriate cable for the attachment to the network either a 120-ohm
twisted pair cable or a 75-ohm coax cable as follows:
  o  120 ohm Twisted Pair Cable Description is shown in Fig. 2.
  o  75 ohm Coax Cable Description is shown in Fig. 3.

Principle of Operation
  o  When the 120-ohm twister pair cable is plugged into the adapter
      connector, the relay located on the communication adapter is
not
      connected to ground through pins 5 and 6.  Therefore it does
not
      activate its contacts, and the internal network impedance is
      equal to 120 o...