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NETWORKING HUB
4. Operation
This chapter describes the Network Hub’s LEDs and operating features. The Hub
is fully compliant with the Ethernet Version 2/IEEE 802.3 Repeater Specification
for CSMA/CD 10-Mbps operation and will function accordingly.
4.1 LEDs
• Power On (PWR) LED: Lights green to show functional DC power.
• Link Status (Link/TX) LEDs: The Networking Hub has a Link/TX LED for
each port, which lights green when the the hub detects that a 10BASE-T
segment is properly connected to that port. Each Link/TX LED will turn OFF
independently if either end of the segment’s cable comes loose, or if the hub
or the device at the other end loses power.
• Receive Packets (RX) LEDs: The RX LEDs, one for each RJ-45 port, flicker
green to show that data packets are being received from the segment
connected to that port. These LEDs provide reassurance of normal network
activity and help you spot abnormal activity.
4.2 Operating Features
• Partitioning and Reconnection: The Networking Hub will automatically
partition any port where 32 consecutive collisions occur or after 6.5 ms of
continuous transmissions. Network integrity is checked every 800 ms, and the
segment is reconnected after one 512-bit packet is transmitted without an
error.
• Preamble Regeneration: As per Ethernet standards, the hub adds bits to the
preambles of output packets so that each output packet contains a minimum
64-bit preamble.
• 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 other
ports.
• Fragment Extension: The hub will automatically add bits to a received data
packet of less than 96 bits (a “fragment”) so that the size of the packet sent on
toward its destination is at least 96 bits, per Ethernet standards.
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