Installing and Upgrading the CSC-C2FCIT FDDI Card and Appliques 25
Testing the Installation
FDDI Applique LED Indicators
Each FDDI applique contains a bank of nine LEDs, which indicate the current line state of each of
the two physical connections on the card. The applique LEDs are shown in Figure 17, and their line
states are listed in Table 6.
Table 6
Line State Indications for PHY-A or PHY-B LEDs
When the ring is operational (when the line protocol is up), the LEDs for each physical connection
(A and B) will oscillate between ILS, ALS, and MLS. ILS will predominate, so LED 2 will glow
most brightly; LED 0 will be slightly dimmer; and LED 1 will be almost completely dark. The
X3T9.5 FDDI specification explains the meaning of these line states in detail.
Figure 17
FDDI Applique Faceplate Showing the LEDs (APP-LSS shown)
0
1
2
State
On
On
On
Line State Unknown (LSU)
On
On
Off
Halt Line State (HLS)
On
Off
On
Master Line State (MLS)
On
Off
Off
Active Line State (ALS)
Off
On
On
Noise Line State (NLS)
Off
On
Off
Quiet Line State (QLS)
Off
Off
On
Idle Line State (ILS)
Off
Off
Off
Elasticity Buffer Overflow/Underflow (OVUF)
A
B
Faceplate
Unused (green)
Unused (yellow)
Unused (yellow)
PHY A LED 0
PHY A LED 1
PHY A LED 2
PHY B LED 0
PHY B LED 1
PHY B LED 2
H1107a
X
M
T
A
R
C
V
A
X
M
T
B
R
C
V
B
