Configuring NC4000 Nodes 3-11
3.5.2
Return Path Transceiver Installation
DANGER Laser Radiation
ā 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.
Return path transceivers get their RF input from the RF amplifier, and output an optical stream to
the next node or to the headend (or hub). The number of transceivers (one or two) depends on the
return segmentation and redundancy requirements. The specific type of transceiver(s) depends on
the return RF frequency from the subscriber (see Table 2.2 on page 2-10) and must be compatible
with the RF amplifier tray (see Note in
3.1 RF Amplifier Tray Installation
on page 3-1). The transceiver
in slot A is required for node monitoring/management.
There are two dedicated transceiver slots on the lid motherboard (Figure 3.7 on page 3-7) with a
second transceiver only needed for redundancy. The DT4250 transceiver is a universal digital
return transceiver capable of operating in multiple modes. It supports two analog return signals
and can be used to transport either a single (1-fer) or two separate returns (2-fer) operating in one
of three bandwidths. DT4250N universal digital return transceivers are further described in
TN-12-010 DT4250N-xx Universal Digital Transceiver Installation and Setup
.
1.
Orient the return transceiver so the connectors (on the bottom) line up with the
corresponding connectors on the lid motherboard. Gently push the transceiver down until
the connectors mate with the motherboard.
2.
Using a flat tip screwdriver, tighten the three screws that hold the transceiver in place.
3.
If the node is powered up, check the transceiverās 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
transceiver(s).
5.
Remove the protective cap from the fiber optic cable and clean the connector, then
connect it to the transceiver.
Repeat Step 1 through Step 5 (above) for the second transceiver if applicable.
After fully configuring a node, you can verify transceiver performance by performing the return
path transceiver setup described in 4.8.1 Return Path Transceiver Setup on page 4-17.
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