Triplett TVR10/100/1000 User Manual

Page 16

testing) are the same for Inline testing. The speed/duplex indicated
is the result of the two devices negotiating to a common speed and
duplex. This is termed the "negotiated speed". Speed and Duplex
are important considerations because two LAN devices will not to
communicate unless they both are operating at the same speed and
duplex.For more detailed information about Data and Link pulses
see Appendix B. If a device has PoE, the PoE LED will light.

Negotiating the speed between two LAN devices. When all de-
vices were 10 Base-T, half duplex, two LAN devices linked together

operated at 10 MB/s, half duplex. Today's devices offer a
mixture of speed and duplex across 10 MB/s, 100 MB/s
and 1000 MB/s. Their capabilities range from being ﬁxed
at one speed and duplex to handling all speeds and
duplexes. To determine the speed of a link, a negotia-
tion may take place between the two LAN devices. The
negotiation normally consists of a mixture of link pulses

and data packets sent between the two devices. As an example,
presume unit A (a 100 MB/s, full duplex device) is connected to a
unit B capable of 100 MB/s and 1000 MB/s, full or half duplex. If typi-
cal, unit A will negotiate with unit B and unit B will reconﬁgure itself
for 100 MB/s, full duplex communication.

Displaying the DATA packet and LINK pulse activity of the

connected device(s). The DATA and LINK LEDs provide
and easy way to identify the device type (does a device
appear to be a hub/switch or a PC) but beyond that, as you

become more familiar with the operation of your network devices,
you will ﬁnd the ability to differentiate between data and link pulses
to be very helpful. See Appendix B for further details about data and
link pulses.

LINK