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PRELIMINARY
XRT79L71
264
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
to indicate an erred condition. The Transmit Section of the XRT79L71 will set the "A" bit-field to "0" in order to
denote an un-erred condition.
This concept of transmitting the FEBE/REI indicator (via the "A" bit) in response to the detection of BIP-4 errors
Figure 118 presents an illustration of a given Near-End Terminal that is exchanging E3 data with the remote
terminal, in an un-erred manner. More specifically, the Receive E3 Framer block has locally computed a BIP-4
value of "0xC" (that was computed over a given incoming E3 frame). Figure 119 indicates that the BIP-4
nibble value (which resides within the very next incoming E3 frame) is of the value "0xC". As a consequence,
there is no BIP-4 nibble error being detected at this time.
In response to this un-erred condition, the Transmit E3 Framer (within the Near-End Terminal) will respond by
setting the "A" bit-field "0". Figure 119 presents an illustration of the Transmit E3 Framer sending this un-erred
indication to the Remote Terminal Equipment.
Next, Figure 120 presents an illustration of a given Near-End Terminal that is detecting a BIP-4 nibble error
within its incoming E3 signal. More specifically, the Receive E3 Framer block has locally computed a BIP-4
nibble of "0xC" (that was computed over a given incoming E3 frame). Figure 120 indicates that the BIP-4
FIGURE 118. A SIMPLE ILLUSTRATION OF A NEAR-END TERMINAL EXCHANGING E3 DATA WITH A REMOTE TERMINAL,
IN AN UN
-ERRED MANNER
FIGURE 119. A SIMPLE ILLUSTRATION OF THE NEAR-END TERMINAL TRANSMITTING THE UN-ERRED INDICATION TO
THE REMOTE TERMINAL EQUIPMENT
Transmit E3
Framer
Receive E3
Framer
Near-End Terminal
Remote
Terminal
Equipment
Remote
Terminal
Equipment
BIP-4 Nibble
Locally Calculated
EM Byte
0xC
Transmit E3
Framer
Receive E3
Framer
Near-End Terminal
Remote
Terminal
Equipment
Remote
Terminal
Equipment
0
A Bit