XRT83VSH28ES Exar, XRT83VSH28ES Datasheet - Page 39

• Manufacturer Part Number: XRT83VSH28ES
• Description: Peripheral Drivers & Components - PCIs 8 CH E1 LIU SH (low cost version)
• Manufacturer: Exar

Specifications of XRT83VSH28ES

• Product Category: Peripheral Drivers & Components - PCIs
• Rohs: yes

REV. 2.0.0
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.
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
redundancy scheme.
F
4.2.4
4.2.5
IGURE
25. S
N+1 Redundancy Using External Relays
Transmit Interface with N+1 Redundancy
IMPLIFIED
Backplane Interface
B
LOCK
Primary Card
Primary Card
Backup Card
Primary Card
Impedence
Impedence
Impedence
Impedence
Internal
Internal
Internal
Internal
Figure 25
D
IAGRAM OF THE
Tx
Tx
Tx
Tx
XRT83VSH28
XRT83VSH28
XRT83VSH28
XRT83VSH28
for a simplified block diagram of the transmit section for an N+1
0.68uF
0.68uF
0.68uF
0.68uF
T
RANSMIT
8-CHANNEL E1 SHORT-HAUL LINE INTERFACE UNIT
36
Line Interface Card
I
NTERFACE FOR
1:2
1:2
1:2
N+1 R
EDUNDANCY
E1 Line
E1 Line
E1 Line
XRT83VSH28