Cisco Headend System Release 2.5 User Guide

1-4 

DHCT Status Reporting Utility 

78-738186-01 Rev B 

This section lists some of the conditions that may contribute to DHCTs becoming 

non-responders. 

Subscribers themselves may be responsible for causing some DHCTs to become non-

responders. The following list contains a few examples of conditions that might exist 

in a subscriber’s home that could cause the subscriber’s DHCT to be a non-responder: 
• 

Subscriber installs a one-way power amplifier—A one-way power amplifier blocks 

return transmissions. 

• 

Subscriber installs a signal splitter—A signal splitter may reduce the strength of 

return transmissions or, in some cases, completely block the return transmission. 

• 

Subscriber connects the DHCT to a light switch or a power strip—The DHCT 

receives no power when the light switch or power strip is turned off. 

The following list contains some examples of DHCT memory and hardware issues 

that might cause a DHCT to become a non-responder: 
• 

Outdated DHCT operating system—Early versions of the operating system used 

in DHCTs had memory issues that might cause a DHCT to malfunction. 

• 

Miscellaneous internal failures—Internal components of the DHCT may fail and 

cause the DHCT to become a non-responder. 

The following list contains some return-path network conditions that might cause a 

DHCT to become a non-responder: 
• 

Laser clipping—Lasers that assist in return path communications may be 

calibrated incorrectly, resulting in a distortion of signal. 

• 

Over-utilization of existing design—Installation technicians may have installed 

more signal splitters on the network than designed. 

• 

Signal interference—The quality of the return transmission may be poor due to 

ingress or intermodulation. 
Note:  Ingress refers to noise from an external source; intermodulation refers to 

noise generated from within the network.