3com 4250T Manual De Usuario

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The Power-up Sequence
25
When the POST has completed, check the Power On Self
 
Test LED to 
make sure that your Switch is operating correctly. 
shows possible 
colors for the LED.
Table 6    Power/Self Test LED colors
In addition, check the Unit LEDs on all Switches in the stack. If a Unit LED 
is off, initialization is not complete. 3Com recommends that you do not 
use the Switch's management interface until the Unit LED is green.
If there is evidence of a problem, see “Solving Problems Indicated by 
LEDs” on 
.
Connecting a 
Redundant Power 
System
You can connect a SuperStack Advanced Redundant Power System 
(3C16071, 3C16071A or 3C16071B) to the Switch. This unit, which is 
also known as an RPS, is designed to maintain the power to your Switch 
if a power supply failure occurs.
For normal redundancy, the unit requires one Type 2A Power Module 
(part number 3C16074A). For full redundancy, the unit requires two type 
2A Power Modules combined using a Type 2 Y-Cable (part number 
3C16078).
CAUTION: The Switch has no ON/OFF switch; the only method of 
connecting or disconnecting mains power is by connecting or 
disconnecting the power cord.
CAUTION: The Switch can only use a SuperStack Advanced Redundant 
Power System output. 
Choosing the Correct 
Cables
All of the ports on the front of the Switch 4200 Family are Auto-MDIX, 
that is they have a cross-over capability. The port can automatically detect 
whether it needs to operate in MDI or MDIX mode. Therefore you can 
make a connection to a port with a straight-through (MDI) or a cross-over 
cable (MDIX).
The Auto-MDIX feature only operates when auto-negotiation is enabled.
Color
State
Green
The Switch is powered-up and operating normally.
Yellow
The Switch has failed its Power On Self Test. 
Off
The Switch is not receiving power.
DUA1730-0AAA04.book  Page 25  Thursday, November 17, 2005  2:59 PM