![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT79L71IB-F_datasheet_100145/XRT79L71IB-F_400.png)
XRT79L71
PRELIMINARY
385
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
PAGE 390. for details on how the Receive E3 Framer block handles the FEBE/REI indicators.
one can configure the Transmit DS3/E3 Framer block to automatically transmit the FERF/RDI indicator to the
remote terminal anytime (and for the duration) that the "Near-End" Corresponding Receive DS3/E3 Framer
Block declares either the LOS, LOF/OOF or AIS defect condition. Figure 178 recaps some of this discussion
by presenting a figure that depicts the Transmit DS3/E3 Framer block automatically transmitting the FERF/RDI
indicator to the "remote terminal equipment" (by setting the "FERF/RDI" bit within each "outbound" E3 frame to
"1") because the "Near-End" Corresponding Receive DS3/E3 Framer block was declaring the LOS defect
condition.
generate the FERF/RDI indicator. In this Section, we will describe how a given Terminal (that contains the
XRT79L71) will respond to receiving the FERF/RDI indicator from the remote terminal equipment.
5.3.2.5.2
The FERF/RDI Defect Declaration Criteria
The Receive E3 Framer block will declare the FERF/RDI defect condition, if it receives a "user-selectable"
number of consecutive E3 frames, in which the FERF/RDI bit-field is set to "1".
The appropriate number of consecutive incoming E3 frames (in which the "A" bit-field are set to "1") prior to the
Receive E3 Framer block declaring the "FERF/RDI Defect condition" can be selected by writing the
appropriate value into Bit 4 (RxFERF Algo) within the "Receive E3 Configuration and Status Register # 1" as
depicted below.
FIGURE 178. FA SIMPLE ILLUSTRATION OF THE "NEAR-END" TERMINAL EQUIPMENT TRANSMITTING THE FERF/RDI
INDICATOR TO THE REMOTE TERMINAL EQUIPMENT
.
Transmit E3
Framer
Receive E3
Framer
Near-End Terminal
Remote
Terminal
Equipment
Remote
Terminal
Equipment
1
A Bit
Declares the LOS Defect
Condition
Declares the FERF/RDI
Defect Condition