EXFO FTB-800 Series for FTB-1 - Manual (Page 60)

Test Setup - Test Applications
50 FTB-700G/800 Series
NI/CSU Emulation
NI/CSU Emulation
Allows DS1 testing in NI/CSU (Network Interface/Customer Service Unit)
emulation mode.

Typical OTN BERT test applications:
Network
under test
Testing Unit DUT Loopback
FTB-700G/800 Series
Network
under test
Testing Unit Testing Unit
FTB-700G/800 Series FTB-700G/800 Series