3Com SuperStack II PathBuilder S330 Reference Manual page 47

OC3/STM-1 LEDs In addition to the common LEDs described earlier in this
chapter, the following LEDs indicate the status of the OC3/STM-1 port. (See
Figure 29.)
OC3/STM-1 Alert (red) — Powers up in the "off" state and illuminates when
a Loss of Signal (LOS), Loss of Frame (LOF), Loss of Pointer (LOP), or Loss of
ATM Frame (LOAF) condition is detected on the incoming OC3/STM-1. If none
of these conditions is present, the OC3/STM-1 ALARM LED is off.
OC3/STM-1 Active (green) — Powers up in the "off" state and illuminates
when the OC3/STM-1 is online.
Figure 29 OC3/STM-1 Port LEDs
Alert
Active
Installation Procedures 33