HFC Enhance
®
NT/NB DFB RETURN PATH TRANSMITTER
1. Overview
Figure #1 illustrates the HEFN**** DFB-based Return Path Transmitters.
2. Installation
1. Power off the NT/NB Node.
2. Open the NT/NB Node; locate the existing return transmitter module in the optical section of the node. The return path
transmitter is located on the left side of the node, underneath the Fiber Management Tray.
3. Swing the Fiber Management Tray up to provide access to the return transmitter(s).
4. Disconnect the fi ber connector and then remove the existing return transmitter and replace it with the new HEFN****
Return Path Transmitter provided. Secure the return path transmitter by tightening the captive screws located on the
module. The RF input connection to the return path transmitter is made at the bottom of the return transmitter modules
DB-style connector.
5. Reconnect the appropriate fi ber connector to the new return transmitter. Dress the fi ber inside the node to prevent
it being damaged or pinched when the node is closed.
(Note: Always clean the fi ber connectors to prevent
contamination. Also ensure that the fi ber connectors are of the same type, mismatching fi ber connectors can
cause low signal level or damage to the fi ber connector faces)
.
6. Tilt the Fiber Management Tray back down into the node and secure.
7. Power the NT/NB Node back on.
8. Optical output power of the HEFN**** Return Path Transmitter can be measured at the 1V/mW OPT PWR Test Point on
the transmitter. Be sure to ground the ground lead of the multimeter to a ground in the node when monitoring these
test points.
9. RF input level into the return path transmitter can be measured at the -20 dB Test Point on the transmitter.
10. The transmitter also features an LED which illuminates GREEN when the transmitter status is nominal and RED when the
transmitter has a fault.
11. When everything is connected and the unit is powered, adjust the level of the transmitter for optimum RF drive level
(see Section #3).
HFC Enhance
®
– NT/NB DFB Return Path Transmitter Installation & Operation Manual
Page 1 of 3
HFC Enhance
®
– NT/NB DFB Return Path Transmitter Installation & Operation Manual
Figure #1 HEFN**** Return Path Transmitter
