3.4.2
Forward Path Receiver Installation
DANGER Laser Radiation
— Avoid any exposure to laser beams. Viewing the laser output with
certain optical instruments (e.g. eye loupes, magnifiers and microscopes) within a distance of 100
mm may pose an eye hazard.
Forward path receivers get their input from the headend (or hub) via optical fiber, and output RF
to the four amplifier buses on the RF amplifier tray. The number of receivers (one to two) depends
if forward RF path redundancy is implemented.
There are four receiver slots on the lid motherboard (Figure 3.7 on page 3-7). For one forward
segment, install the single receiver in slot B.
For a single forward segment with redundant receivers for failover, place receivers in slots B and C.
1.
Orient the forward receiver so the connectors (on the bottom) line up with the
corresponding connectors on the lid motherboard. Gently push the receiver down until the
connectors mate with the motherboard.
2.
Using a flat tip screwdriver, tighten the three screws that hold the receiver in place.
3.
If the node is powered up, check the receiver’s ON LED.
4.
Identify the appropriate fiber optic cable for this receiver.
If you are going to use fiber optic jumpers in the actual installation, install them now. The
jumpers run from the fiber tray to the forward path receiver(s) and return path transceiver(s).
If you are not going to use jumpers in the actual installation, but want to test the configured
NC4000 in the shop/lab environment, connect the appropriate temporary test cable to the
receiver.
5.
Remove the protective cap from the fiber optic cable and clean the connector, then
connect it to the receiver.
Repeat Step 1 through Step 5 (above) for a redundant receiver if applicable.
After fully configuring a node, you can verify receiver performance by performing the forward path
receiver setup described in 4.7.1 Forward Path Receiver Setup on page 4-10. Table 2.1 on page 2-8
lists the forward path receivers currently available for the NC4000 node.
3.5
Return Path Configuration
Note
Where specific procedures (such as segmentation) are applicable to both
Chapter 3, Configuring NC4000 Nodes and Chapter 4, Installing NC4000 Nodes, you
are referred to Chapter 4, where the context is installing the node in the network.
3.5.1
Return Path Segmentation
Return path segmentation refers to the number of return RF streams coming into the NC4000.
The NC4000 can support one or two return streams with a single DT4250. Configure return
segmentation per 4.8.2.1 Return Path Segmentation—OA4324HG RF Amplifiers on page 4-18.
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