363-206-305
Circuit Pack Descriptions
Issue 3 June 2000
7-17
Figure 7-7. BBF1B DS1 Circuit Pack Block Diagram
Protection Circuitry
7
Optional DS1 circuit pack protection is provided with on-board relays on the
DSX-1 side and with logic selectors at the VT-G level on the OLIU circuit pack. The
SYSCTL controls these relays through two serial interfaces so that a failure of one
serial interface to the DS1 does not prevent control of the relays. If +5 V power on
the DS1 fails, the relays default to the protection state. If the SYSCTL is removed,
the relays remain in their current state.
When a DS1 circuit pack is inserted, the relays are in the protection state until the
SYSCTL determines that the circuit pack is good. Shorting contacts are provided
in the backplane connectors so that when the circuit pack is removed, the DSX-1
cable pairs short through to the protection bus.
VT 1.5
VT-G
Timing
LBO
Adds (Removes)
LBO
DS1 to VT 1.5
Processor
Adds (Removes)
DS1 #3
DS1 #4
Prot. Sw.
Bus
To/From
Loopback
LBO
DS1 to VT 1.5
Processor
Adds (Removes)
VT OH
LBO
DS1 to VT 1.5
Processor
Adds (Removes)
VT OH
DS1 to VT 1.5
Processor
VT OH
To/From
DSX-1
VT OH
VT 1.5
VT 1.5
VT 1.5
VT 1.5
DS1 #1
DS1 #2
Prot. Sw.
Bus
To/From
Loopback
Loopback
Loopback
Prot. Sw.
Bus
To/From
Byte
Interleave &
(Disinterleave)
Control
+5V Power
To/From
SYSCTL
Circuit Pack
Prot. Sw.
Bus
To/From
Intrashelf
To/From
OLIU CPs
(Service &
Protection)
From
OLIU CPs
(Service &
Protection)
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