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Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide
OL-17309-02
Chapter 4 Connecting the Cisco uBR7225VXR Router to the Cable Headend
Two-Way Data Headend Architecture
Two-Way Data Headend Architecture
Figure 4-1 shows a typical headend configuration configured for two-way data, including digitized voice
and fax.
Figure 4-1 Typical Cable Headend Configuration for Two-Way Data
Cisco
uBR7225VXR
Downstream
271671
Upstream
0 dBmV
6 dB
attenuator
40 dB
attenuator
3 dB
attenuator
Optical
receiver
Fiber-optic
cable
Distribution
network
+17 dBmV +13 dBmV
Cable
modems
+48 dBmV
+31 dBmV
2-way
splitter
+10 dBmV
6 dB
attenuator
40 dB
attenuator
8 dB
attenuator
+18 dBmV
+42 dBmV
+58 dBmV
2-way
splitter
+10 dBmV
6 dB
attenuator
40 dB
attenuator
21 dB
attenuator
+31 dBmV
+42 dBmV
+49 dBmV
+50 dBmV
2-way
splitter
+10 dBmV
Laser
transmitter
Broadcast
Narrowcast
0 to 20 dB
attenuator
(as required)
8-way
tap
3-way
splitter
+17 dBmV
video carrier
(typical)
+7 dBmV
data carrier
(typical)
Optical
splitter
Node 1
Node 2
Downstream
forward
test point
Main
headend feed
X
X
X
Reverse optical
transmitter
Modem
transmit
levels
Modem
transmit
levels
Modem
transmit
levels
Reverse optical
transmitter
Reverse optical
transmitter
Optical
receiver
Fiber-optic
cable
Distribution
network
+17 dBmV
Optical
receiver
Fiber-optic
cable
Distribution
network
+17 dBmV
Downstream
(0 to +5 dBmV)
Cable
modem
LH
C
Diplex filter
Downstream
(0 to +5 dBmV)
Cable
modem
LH
C
Diplex filter
Downstream
(0 to +5 dBmV)
Cable
modem
LH
C
Diplex filter