XRT83SL314
xr
REV. 1.0.1
14-CHANNEL T1/E1/J1 SHORT-HAUL LINE INTERFACE UNIT
31
FIGURE 25. SIMPLIFIED BLOCK DIAGRAM OF THE RECEIVE INTERFACE FOR 1:1 AND 1+1 REDUNDANCY
3.3.4
N+1 Redundancy Using External Relays
N+1 redundancy has one backup card for N primary cards.
Due to impedance mismatch and signal
contention, external relays are necessary when using this redundancy scheme. The relays create complete
isolation between the primary cards and the backup card. This allows all transmitters and receivers on the
primary cards to be configured in internal impedance, providing one bill of materials for all interface modes of
operation. The transmit and receive sections of the LIU device are described separately.
"High" Impedence
Internal Impedence
Backplane Interface
Primary Card
Backup Card
XRT83SL314
Rx
T1/E1 Line
Rx
1:1
XRT83SL314