Cabletron Systems MICROMMAC-22T User Manual

This chapter describes and explains how to use LANVIEW LEDs and the 
Liquid Crystal Display (LCD) to troubleshoot physical layer network 
problems. The chapter concludes with an overview of the POWER UP 
Diagnostic Test.

LANVIEW LEDs (located on the front panel) are Cabletron Systems’ 
built-in visual diagnostic and status monitoring system. Use the LEDs to 
monitor network status or diagnose physical-layer network problems. 
Table 5-1 below lists and describes front panel LEDs.

Lobe Port Status
(Ports 1-24)

Off
Green
Red
Red (blinking)

No Link/Port Enabled
Link/Port Enabled
No Link/Port Disabled
Link or Ring Speed Fault/Port Disabled

16Mb/s
(Ring Speed)

Yellow
Off

16MbpsRing Speed
4 Mbps Ring Speed

ACT
(Network Activity)

Green (Flashing)
Red (Flashing)
Off

Good Frames
Beacon Recovery Running
No Activity

MGMT
(Network Management)

Green
Red

Management Agent Active
Management Agent Not Active

CPU
(Central Processing Unit)

Off
Green (Flashing)
Green (Blinking)
Red
Yellow
Yellow/Green

No Power
CPU Initializing
CPU Functioning (normal)
CPU Not Functioning
Diagnostic Testing
Booting

NOTE: “Flashing” indicates an irregular LED pulse. “Blinking” 
indicates a steady LED pulse.