EXFO FTB-800 Series for FTB-1 - Manual (Page 103)

Test Setup - Test Configurator, Timer, and System
NetBlazer 93
Modify Structure Button

Loopback Mode
Note: Only available for Smart Loopback Ethernet test application.
Transparent (Pseudo-Physical) check box when selected (cleared by
default), determines that the Smart Loopback operates as a physical
loopback by transmitting all received frames unaltered and without
discrimination. When the check box is cleared, the Loopback mode is
selectable from Loopback on page 218.
In transparent mode, the Network tab and the Ping & Trace Route
functions are not available.
Note: The Transparent mode is intended to be used for point-to-point topology;
not for switched or routed networks. Use the Transparent mode with
caution because all received frames are looped back without
discrimination.