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CHAPTER 4: Operation
4. Operation
• Partitioning and re-connection—
The 10BASE-T MiniHub will
automatically partition any port
where 32 consecutive collisions
occur or after 6.5 milliseconds of
continuous transmissions.
Network integrity is checked
every 800 milliseconds and
segment re-connection occurs
after one 512-bit packet is
transmitted without an error.
• Preamble regeneration—The
10BASE-T MiniHub will add bits
to the preamble so that the
output packet contains at a
minimum a 64-bit preamble
per the Ethernet standard.
• Collisions—When carrier is
detected simultaneously on
multiple ports, a jam pattern is
generated on each port to create
a collision condition. When a
collision signal from one port
is detected, it generates a jam
pattern to the other ports.
• Fragment extension—The
10BASE-T MiniHub will
automatically add bits to a
received data packet of less than
96 bits (a “fragment”) so that the
minimum output packet to the
other port is 96 bits long.
This section details the various
operational features of the 10BASE-
T MiniHub, including a description
of the LED indicators. The 10BASE-
T MiniHub is fully compliant with
the Ethernet Version 2/IEEE 802.3
repeater specification for CSMA/CD
10 Mbps operation and will function
accordingly.
• Power On (PWR) LED—lights
green to show functional DC
power.
• Link Status (Link) LED—The
10BASE-T MiniHub includes a
Link LED for each port. It
indicates by illuminating in
green that there is proper
connectivity on its 10BASE-T
network segment. The Link LED
will turn off if connectivity is lost
between the ends of the segment
or a loss of power occurs in the
unit at either end.
• Receive Packets (RX) LED—The
RX LEDs, one for each
RJ-45 port, illuminate
intermittently in green to
indicate that data packets are
being received from the
segment. This provides a visual
indication of network activity,
and is also helpful in
troubleshooting.
