Triplett TVR10/100/1000 User Manual

Page 29

If only one column of LEDs comes on in either jack conﬁguration
you are not communicating. If this is the case, unplug both devices
from the TVR1000 and then test the devices individually using the
Green jack. The device that does not show any activity on the LEDs
is causing the problem. If a remote device is showing no activity,
there may be nothing connected at the other end of the cable. See
Test Example #4 for a quick test for a device connection on the
other end of the cable.

Note:When all devices were 10 Base-T, half duplex, two LAN
devices linked together operated at 10 MB/s, half duplex. Now
there is a mixture of speed and duplex across 10 MB/s, 100 MB/s
and 1000 MB/s devices. 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 negotiation 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. Further presume that when unit B is ﬁrst turned ON its
speed is 100MB/s, half duplex (its "default" speed). If typical, unit
A will negotiate with unit B and unit B will reconﬁgure itself for 100
MB/s, full duplex communication. The TVR1000 displays the link
pulses and data packet activity as well as the speed/duplex of the
link. See Appendix B for further discussion.