XRT83L314 Datasheet, PDF (43/84 Pages) Exar Corporation – 14-CHANNEL T1/E1/J1 LONG-HAUL/SHORT-HAUL LINE INTERFACE UNIT

XRT83L314
14-CHANNEL T1/E1/J1 LONG-HAUL/SHORT-HAUL LINE INTERFACE UNIT
REV. 1.0.0
4.3.5 Transmit Interface with N+1 Redundancy
For N+1 redundancy, the transmitters on all cards should be programmed for internal impedance. The
transmitters on the backup card do not have to be tri-stated. To swap the primary card, close the desired
relays, and tri-state the transmitters on the failed primary card. A 0.68uF capacitor is used in series with TTIP
for blocking DC bias. See Figure 38 for a simplified block diagram of the transmit section for an N+1
redundancy scheme.
FIGURE 38. SIMPLIFIED BLOCK DIAGRAM OF THE TRANSMIT INTERFACE FOR N+1 REDUNDANCY
Backplane Interface
Primary Card
XRT83L314
Tx
0.68uF
Internal
Impedence
Primary Card
XRT83L314
Tx
0.68uF
Internal
Impedence
Primary Card
XRT83L314
Tx
0.68uF
Internal
Impedence
Backup Card
XRT83L314
Tx
0.68uF
Internal
Impedence
Line Interface Card
1:2
1:2
1:2
T1/E1 Line
T1/E1 Line
T1/E1 Line
39