Cisco SR2016T-NA Reference Manual page 1019

Chapter 6 Cable CPE Commands
cable-modem upstream preamble qpsk
To enable the QPSK modulation scheme in the upstream direction from the cable interface to the CMTS,
use the cable-modem upstream preamble qpsk command in cable interface configuration mode. To
disable upstream modulation for the interface, use the no form of this command.
Cisco uBR904, uBR905, uBR924, uBR925 cable access routers, Cisco CVA122 Cable Voice Adapter
Syntax Description
This command has no arguments or keywords.
Defaults Enabled
Command Modes Interface configuration (cable interface only)
Command History Release
11.3(4)NA
12.0(4)XI1
12.1(3)XL
12.1(5)XU1
12.2(2)XA
Examples The following example shows how to configure the cable interface for QPSK modulation on the
upstream:
Router(config)# interface cable-modem 0
Router(config-if)# cable-modem upstream preamble qpsk
Router(config-if)#
Related Commands Command
cable-modem compliant bridge
cable-modem downstream
saved channel
cable-modem fast-search
cable-modem voip best-effort
OL-1581-07
cable-modem upstream preamble qpsk
no cable-modem upstream preamble qpsk
Modification
This command was introduced for the Cisco uBR904 cable access router.
Support was added for the Cisco uBR924 cable access router.
Support was added for the Cisco uBR905 cable access router.
Support was added for the Cisco CVA122 Cable Voice Adapter.
Support was added for the Cisco uBR925 cable access router.
Description
Enables DOCSIS-compliant transparent bridging for the cable
interface at startup.
Modifies the saved downstream channel setting and upstream power
value on the cable interface.
Enables a faster downstream search algorithm on the cable
interface.
Allows voice calls to be sent upstream over the cable interface via
best effort.
Cisco Broadband Cable Command Reference Guide
cable-modem upstream preamble qpsk
6-17