Grass Valley NV5256 v.1.8 - Manual (Page 32)

24 Rev 1.8 • 08 Jul 11
3. Detail
Expansion
Expansion
The NV5256 can be expanded to a maximum of 512 ports. To accomplish this, interconnect two
NV5256 frames. The frames share each other’s input space. The first frame receives commands
from the router control system and acts as the master to the second frame.
The interconnect is simple and uses the frame expansion connectors at the back of the frame.
Figure 3-4. Expansion Connectors and Expansion Connections
The frame expansion connectors are driven by the frame expansion cards (EM0502-00) in the
frame. A frame really requires only one expansion card; the second is recommended for redun-
dancy. If both cards and links are installed, the frame will switch from one expansion link to the
other if the current link goes bad.
A frame expansion card multiplexes (TDM) the local frames inputs and sends them out the frame
expansion “Out” port to the other frame. It receives the other frame’s inputs from the “In” port.
Connect the primary input on the master frame to the slave frame’s primary output. Connect the
primary output on the master frame to the primary input on the slave frame. If you have a redundant
expansion card, connect the secondary expansion connections the same as the primary connections.
The expansion cards have built-in redundancy control. Each card reports its own health to the other
card and to the router control card. The first healthy card to start up during initial boot takes over
the expansion link and is the main transmitter and receiver. If, at any time, the link becomes
“unhealthy,” the other expansion card takes over the expansion link if it is healthy.
You can use 75 Ω Belden 8281 cable, up to 250 meters, to make these connections.
The Expansion Card
The NV5256 has 2 slots for expansion cards. A stand-alone router requires no expansion card. One
card is required for expansion. The second expansion card provides redundancy.
Release Switch
An expansion card has a front panel reset switch. It forces the active card to release, so that the
other expansion card can take over.
PS 1
LEFT
PRIMARY
EXPANSION
SECONDARY
EXPANSION
IN
OUT
AES
REF
OUT
IN
AES
REF
OUT
OUT
Belden
8281
NV5256, “Slave” NV5256,”Master”
Ports 1–256 Ports 257–512
Exp. In
Exp. Out
AES Ref
Primary
Exp. In
Exp. Out
AES Ref
Secondary
Pri. AES Ref In
Sec. AES Ref In
10/100BaseT 10Base2 NV9000
Exp. In
Exp. Out
AES Ref
Primary
Exp. In
Exp. Out
AES Ref
Secondary
Pri. AES Ref
Sec. AES Ref
10Base2
50W coax