EXFO FTB-8500 Series for FTB-500 - Manual (Page 269)

Pattern Tabs
Ethernet and Fibre Channel Application 255
Pattern RX
Pattern RX
Press TEST, and Pattern.
Configuration
Note: See Configuration on page 252 for more information on Test Pattern,
Invert, and User Pattern.
Alarm Analysis
Pattern Loss
For Ethernet, a Pattern Loss is declared when the test sequence and the
reference sequence can be unambiguously identified as out of phase.
For Fibre Channel, a Pattern Loss is declared when at least four
consecutive words having at least one bit error are detected causing a loss
of pattern synchronization. Not supported on FTB-8510G.
No Traffic is declared when no pattern traffic has been received in the last
second.