EXFO FTB-800 Series for FTB-1 - Manual (Page 190)

Test Setup - Test Configurator, Timer, and System
180 FTB-700G/800 Series
RFC 2544 - Subtests

Latency Threshold / Round-Trip Latency Threshold allows to set the
threshold value as the maximum delay in ms or μs. The range is from
0.5 to 8000.0 ms (default is 125.0 ms) and it applies to all frame sizes
when applicable. For Dual Test Set, only available with Round-Trip
Latency Measurement Mode (see Latency Configuration on
page 177).

One-Way Latency Threshold, available for Dual Test Set with
One-Way Latency Measurement Mode (see Latency Configuration on
page 177), allows to set the maximum one-way latency value in
millisecond, allowed for all frame sizes: 0.005 to 500 ms (default is
125 ms).

Latency Unit allows to either select ms or μs as the reference unit for
the Latency Threshold.