
PRELIMINARY
XRT79L71
148
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
Conversely, if the Near-End Receive DS3/E3 Framer block detects an error in the incoming F, M or CP bits,
then it will notify the remote terminal of this fact, by forcing the Near-End Transmit DS3/E3 Framer block set the
FEBE bits, within an outbound DS3 frame which is destined for the remote terminal to some pattern other than
Figure 65 illustrates the Near-End Receive DS3/E3 Framer block receiving an erred DS3 frame from the
remote terminal. In this figure, the Near-End Receive DS3/E3 Framer block is receiving a DS3 frame, within a
CP bit that is of the value "1".
This value does not match the locally computed CP bit value of "0".
Consequently, there is an error in this DS3 frame.
Figure 66 illustrates the subsequent action of the Near-End Transmit DS3/E3 Framer block, which will transmit
a DS3 frame, with the FEBE bit-fields set to some pattern other than "1, 1, 1" to the remote terminal. In this
case, the Transmit DS3/E3 Framer block is setting the FEBE bits to the value [0, 1, 1]. This signaling indicates
that the Near-End Receive DS3/E3 Framer block has received an erred DS3 frame the remote terminal.
FIGURE 64. ILLUSTRATION OF THE NEAR-END TRANSMIT DS3/E3 FRAMER BLOCK TRANSMITTING A DS3 FRAME TO
THE REMOTE TERMINAL WITH THE
FEBE BITS SET TO "1, 1, 1"
FIGURE 65. ILLUSTRATION OF THE NEAR-END RECEIVE DS3/E3 FRAMER BLOCK RECEIVING A DS3 FRAME FROM
THE REMOTE TERMINAL WITH AN INCORRECT
CP BIT
Transmit DS3
Framer
Receive DS3
Framer
Near-End Terminal
Remote
Terminal
Equipment
Remote
Terminal
Equipment
FEBE bits
11
1
Outbound DS3 Frame
Transmit DS3
Framer
Receive DS3
Framer
Near-End Terminal
Remote
Terminal
Equipment
Remote
Terminal
Equipment
Detecting F-bit Errors
Erred DS3 Data-stream