JDSU NT850 Guia do Utilizador descarregar pdf (Página 40)

Chapter 3 Performing Network Tests

Performing Port Discovery Tests

24 LanScaperPRO Network Tester User’s Guide

If a voltage is detected, the test terminates, and the

user is offered the option to press the TEST key to

run the PoE test to try to identify the voltage found.

(See “Performing PoE Tests” on page 36.)

If no voltages are found, the test for active Ethernet

devices commences. If the remote device is running

in Auto-Negotiation mode, the LanScaperPRO

detects and decodes the Fast Link Pulses (FLP). The

advertised Ethernet speeds, duplex mode, wiring

mode, and polarity of the transmit pair appears. The

wiring mode is indicated by reference to the type of

device that would normally transmit on that pair -- the

hub/switch or NIC -- assuming straight through

cabling. With a cross-over cable present, a NIC

would be labeled as a hub, etc. The AUTO indication

appears if the device connected is capable of auto-

MDI / MDI-X transmit/receive pair swapping.

If no Auto-Negotiation pulses are detected, the

LanScaperPRO attempts to wake a “sleeping” port

by sending out FLP bursts for a short time. Some

Ethernet ports are inactive while not connected in

order to save power. These are known as “sleeping”

ports and depend on the incoming FLP bursts to

wake them into active mode. If the port responds, the

advertised Ethernet speeds, duplex mode, wiring

mode, and polarity of the transmit pair appears.

If no active Ethernet port has been detected, the

LanScaperPRO attempts to connect in both 100 and

10 MB modes in non-Auto-Negotiation mode. If

successful, the connection speed and wiring mode

LanScaperPRO_User_Guide.book Page 24 Friday, January 25, 2008 1:14 PM

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JDSU NT850 Guia do Utilizador Página 40