Cobalt Digital COMPASS 9121 3G_HD_SD-SDI_ASI Redundancy Switch - Manual (Page 9)

9121-OM (V1.2) 9121 PRODUCT MANUAL 1-5
Introduction
9121 Functional Description
9121 Functional Description
Figure 1-1 shows a functional block diagram of the 9121. The 9121 3G/HD/
SD-SDI / ASI Redundancy Switch allows GPI or Ethernet/SNMP changeover
control between two SDI or ASI sources to a common SDI or ASI output.
Output routing uses a latching relay to retain the selected I/O path even if the
card/frame is powered down or card is removed from its slot.
An SDI failover function is provided using a main path preference of SDI IN A :
If SDI IN A goes invalid, then SDI IN B is selected. If SDI IN A goes valid again,
failover automatically reverts to the SDI IN A input. Switchover can also be
manually selected (in which case the selection is persistent even if the card is
removed from its slot).
Note: Automatic failover operation is specified for supported SDI formats only.
Failover usage when carrying signals other than SDI should utilize the GPI
inputs controlled by suitable external monitoring devices.
The 9121 is very straightforward in operation in that the signal path is via a
direct relay path output (alternately, the selected input is available via
non-relay coupled 4x cable drivers). The relay signal path is entirely passive,
with the entire signal package kept intact with no modification of the signal.
Defeatable reclockers for the four non-relay outputs allow the card to pass
digital signals other than SDI and ASI on these DA outputs.
Figure 1-1 9121 Functional Block Diagram
Input Select
Latching Relay
(on Rear
Module)
SDI / ASI
In A
Software-Based
Monitor/Control
4x DA
Outputs
Latched Relay
SDI / ASI Output
SDI / ASI
In B
Signal Validity
Check
Ethernet Control
(DashBoard, SNMP)
GPI Control
EQ/Reclock
GPO Status
9121BDV1.0 LB68