EXFO FTB-8500 Series for FTB-500 - Manual (Page 28)

Physical Interfaces and LEDs
14 FTB-8500 Series and FTB-8120NGE/8130NGE
FTB-8510B Model

LEDs for Optical Ports
LED Status Description
LASER
(Red) On An optical signal is generated
Off No optical signal is generated
LINK/ACT
(Green) On Link up.
Off Link down.
Flashing TX/RX activity.
DUPLEX
(Yellow)
Available
with Ethernet
interface only
On Full Duplex mode.
Off Half Duplex mode, or when using
100Base-X or Fibre Channel interface.
Flashing Collisions are detected in half duplex mode.