LEDs and Switches
B-4
893-743-A
Reset Button
A recessed reset button on the front panel of the Model 281xSA hub is
accessible using a jeweler’s screwdriver or similar pointed implement (see
Figure B-3). Use this button to reset the Model 281xSA hub. Resetting the
Model 281xSA hub causes it to go through the complete download/local load
process. The reset is similar to turning the Model 281xSA hub power off and
then back on, except that data integrity is not interrupted during a reset and is
interrupted during a power recycle.
Figure B-3. Reset button
MDI-X/MDI Switch
Model 281xSA hubs allow you to configure port 1 as an MDI or MDI-X port.
Media dependent interface (MDI) is specified by the IEEE 802.3i 10BASE-T
Standard to be the electrical and mechanical interface to the UTP wire. An MDI
port transmits out to the UTP wire on pins 1 and 2 (pair 2 of the 4-pair UTP
cable), and receives from the UTP wire on RJ-45 pins 3 and 6 (pair 3 of
the 4-pair UTP cable).
MDI-X/MDI
1
2
3
4
5
Link
Part
RS-232
5
Reset
System Operation
4664