10Base5

A type of cable used for LAN connections.

Also known as ThickEthernet.

uses an AUI connector

Can be used to create a truly passive network sniffer as below

Clipping the AUI

The easiest system to clip is 10-mbps using the old AUI transceiver. Note that in today's networking, such equipment is hard to find and expensive to buy "new", but littered all over the place as used equipment. You should consider stockpiling such equipment now, especially PCI Ethernet cards with transceivers.

Other forms of Ethernet are not easily altered. Thin-coax Ethernet uses the same wire for both transmitting/receiving. 10-BASE-T Ethernet requires a link heartbeat on the transmit line so that the hub knows it is connected. In short, only the AUI port contains pins that can be clipped without affecting the operation of the device.

1 8

_ \ . . . . . . . . /

\ . . . . . . . /

\-------------/

9 15

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Pin Sgnl Description

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1 GND 2 CI-A Control In Circuit A 3 DO-A Data Out Circuit A 4 GND 5 DI-A Data In Circuit A 6 VC Voltage Common 7 - 8 GND 9 CI-B Control In Circuit B

10 DO-B Data Out Circuit B 11 GND 12 DI-B Data In Circuit B 13 VP +12 Volts DC 14 GND 15 GND

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Cutting pings 3 and 10 will stop transmission. The easiest way is to clip the pins on the connector rather than the wire itself.