EXFO FTB-800 Series for FTB-1 - Manual (Page 402)

Test Functions
392 FTB-700G/800 Series
FDL - Bit-Oriented Message
FDL - Bit-Oriented Message
Allows to set and configure the Bit-Oriented Messages (BOM) of the
Extended Super-Frame (ESF).
Note: FDL is only available for DS1 interface with ESF framing. For Dual RX test,
FDL is only available for the DS1 TX/RX port 1.
From the Test menu, tap Functions, FDL, and the Bit-Oriented Message
tab.
Generated Messages

Priority
Codeword: The Bit-Oriented Message codewords are priority
messages sent over the Data-Link. These messages are mostly used for
networking operation and maintenance. A Bit-Oriented Message
consists of 8 consecutive ones followed by a byte starting and ending
by zeros.
Injects generates the selected codeword priority message.

Command/Response
Codeword Pattern
RAI 00000000 11111111
Loopback Retention and Acknowledge 00101010 11111111
RAI-CI
00111110 11111111