Specifications

Release Notes for Cisco uBR904 Cable Access Router for Cisco IOS Release 12.0(7)T 13
Supplemental and Corrected Text for the Cisco uBR904 Cable Access Router
The correction should read: “For the Cisco uBR904 cable access router, both the IRC (Incrementally
Related Carrier) and HRC (Harmonically Related Carrier) plans are supported. Most of the IRC
channel slots overlap the EIA plan. For the Cisco uBR904 cable access router, both the IRC and
HRC plans are supported.
The list of downstream search bands added for HRC have appropriate center frequencies and step
values for an HRC channel plan. The expanded search band list may increase the amount of time
required by the Cisco uBR904 cable access router to acquire the downstream signal on the HRC
channel plan, which can add to the total time for complete registration of the Cisco uBR904 cable
access router the very first time it is added to the cable system.”
Supplemental and Corrected Text for the Cisco uBR904 Cable Access Router
The following is updated information to the “Cisco uBR904 Cable Modem Installation and
Configuration Guide.”
Data transmitted to a Cisco uBR904 cable access router from the CMTS shares a 26 or 27 Mbps,
6 MHz data channel in the 88 to 860 MHz range. The Cisco uBR904 cable access router shares an
upstream data rate of up to 10 Mbps on a 200 kHz-wide to 3.2 MHz-wide channel in the 5 to 42 MHz
range.
Note End-to-end throughput varies based on the design and loading of network components, the
mix of traffic, the processing speed and interface of the host servers, the processing speed and local
Ethernet performance of the subscriber’s computer, and other parameters.
The Cisco uBR904 cable access router supports 64 or 256 Quadrature Amplitude Modulation
(QAM) downstream, and Quadrature Phase Shift Keying (QPSK) or 16 QAM upstream
transmission.
Table 3 Cisco uBR904 Cable Access Router Data Specifications
Description Downstream Values Upstream Values
Frequency Range 88 to 860 MHz 5 to 42 MHz
Modulation 64 QAM
256 QAM
QPSK
16 QAM
Data Rate 30 Mbps/64 QAM
(27 Mbit/sec after FEC overhead)
42.8 Mbps/256 QAM
(36 Mbit/sec after FEC overhead)
QPSK—320 Kbit/sec to 5 Mbit/sec
16 QAM—640 Kbit/sec to 10 Mbit/sec
Bandwidth 6 MHz 200K, 400K, 800K, 1.6M,
3.2 MHz
FEC RS (122, 128) Trellis Reed Solomon
One Channel Receive level of digital signal
-15 to +15 dBmV
Note Most field measurements are of nearby
or adjacent analog signal, which is normally
+6 to +10 dB (system specific) above the
digital signal level
QPSK— +8 to +58 dBmV
16 QAM— +8 to +55 dBmV