XRT83SL28
8-CHANNEL E1 SHORT-HAUL LINE INTERFACE UNIT
xr
REV. 1.0.0
3.2.5 Transmit Interface with N+1 Redundancy
For N+1 redundancy, the transmitters on all cards can 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. A 0.68uF capacitor is used in series with TTIP for blocking DC bias. See Figure 23 for a simplified
block diagram of the transmit section for an N+1 redundancy scheme.
FIGURE 23. SIMPLIFIED BLOCK DIAGRAM OF THE TRANSMIT INTERFACE FOR N+1 REDUNDANCY
Backplane Interface
Primary Card
XRT83SL28
Tx
Internal Impedance
0.68uF
Primary Card
XRT83SL28
Tx
Internal Impedance
0.68uF
Primary Card
XRT83SL28
Tx
Internal Impedance
0.68uF
Backup Card
XRT83SL28
Tx
Internal Impedance
0.68uF
Line Interface Card
1:2
1:2
1:2
E1 Line
E1 Line
E1 Line
28