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COM3000 Integrator’s
Installation Manual
Date: January 2024
Version 1.1
11
DISTRIBUTION NETWORKS
11.1
RF NETWORKS
RF networks need to pass digital signal tests per industry standards. Care should be taken to inspect the system
for old crimp style connectors, inferior quality amplifiers, taps and splitters. Wall plate splices and TV jumpers
should also be inspected and replaced, as necessary.
Signal levels should be within industry specifications. 0-5dBmV (+/-3dBmV) with >38dB Modulation Error Rate
(MER) at the TV.
If you are not experienced with digital RF networks it is recommended you contract a qualified RF system
technician to design, install, and troubleshoot the RF plant.
RF Channel Lineup
Determine in advance what networks the customer will require on the system and the channel assignments for
each.
Assign RF carriers to each network. If possible, start RF channel lineup at Ch. 23 or higher (super-band). This will
eliminate possible signal ingress into the RF plant from VHF broadcast signals and keep the property signal out
of the aeronautical frequencies in the 126
–
134 MHz range.
The COM3000 can modulate up to three DIRECTV high-definition programs on one 6MHz QAM carrier.
Do not combine higher bandwidth local, sports, and premium channels on the same QAM carrier.
In some markets local channels may exceed 18 Mbps.
It is a recommended best practice to monitor channels for peak bandwidths and not to exceed an average bit
rate greater than 35mbps per QAM channel.
11.2
IP NETWORKS
IP Networks need to utilize multicast address schemes.
Switches must be enabled for IGMP (Internet Group Management Protocol).
Network Cabling must be installed in accordance with industry standards.
The COM 400 has an internal layer two switch. This switch is for the internal network connecting multiple COM5X
cards across the backplane and is not intended to be utilized as a network switch.
IP Channel Lineup
Each Tuner / Channel in an IP system must be assigned a multicast IP address.
Multicast address start with 224.
–
239. as the first octet of the IP address.
XXX.0.0.XXX and XXX.128.0.XXX carry multicast control packets and should never be used.