XRT73L02M View Datasheet(PDF) - Exar Corporation
Part Name
Description
MFG CO.
'XRT73L02M' PDF : 46 Pages View PDF
xr
REV. 1.0.0
TWO CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
FIGURE 25. ANALOG LOOPBACK
TCLK
TPDATA
TNDATA
1
HDB3/B3ZS
ENCODER
TIMING
CONTROL
Tx
XRT73L02M
TTIP
TRING
RCLK
RPOS
RNEG
1
HDB3/B3ZS
DECODER
DATA &
CLOCK
Rx
RECOVERY
1 if enabled
2 if enabled and selected in either Receive or Transmit path
RTIP
RRING
8.2.2 DIGITAL LOOPBACK:
The Digital Loopback function is available either in Hardware mode or Host mode. When the Digital Loopback
is selected, the transmit clock (TxClk_n) and transmit data inputs (TPOS_n & TNEG_n) are looped back and
output onto the RxClk_n, RPOS_n and RNEG_n pins as shown in Figure 27. The data presented on TxClk,
TPOS and TNEG are not output on the TTIP and TRING pins.This provides the capability to configure the pro-
tection card (in redundancy applications) in Digital Loopback mode without affecting the traffic on the primary
card.
NOTE: Signals on the RTIP_n and RRING_n pins are ignored during digital loop back.
FIGURE 26. DIGITAL LOOPBACK
TCLK
TPDATA
TNDATA
1
HDB3/B3ZS
ENCODER
TIMING
Tx
CONTROL
TTIP
TRING
RCLK
RPOS
RNEG
1
HDB3/B3ZS
DECODER
DATA &
CLOCK
Rx
RECOVERY
1 if enabled
2 if enabled and selected in either Receive or Transmit path
RTIP
RRING
I
8.2.3 REMOTE LOOPBACK:
With Remote loop back activated as shown in Figure 28, the receive data on RTIP and RRING is looped back
after the jitter attenuator (if selected in receive or transmit path) to the transmit path using RxClk as transmit
timing. The receive data is also output via the RPOS and RNEG pins.
41
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