dsl power-cutback command

[eurobadger]

Hi all

I have seen the dsl power-cutback command in a config for the first time. I looked on cisco.com, and it gives me a syntax for the command, but I am not sure what it does and how it is applied.

If the config has:

dsl power-cutback 1

applied to the ATM interface, and the default value is 31, what is the designer doing here?

Thanks
EB

 

[burtsbees]

The power levels at which DSL modems transmit upstream data must be carefully controlled so that the modem signals do not interfere with the voice communications over the twisted-pair line. Current power level configurations include providing a predetermined power cutback (e.g., 80%) for all applications
of a particular modem model. These cutback levels are typically selected based on a worst case scenario basis. Providing a predetermined power cutback level for all DSL modems results in most modems operating at less than peak efficiency.

Power cutback is typically provided by one or more filters and/or gain control units. For example, the modem can include a bandpass filter that passes frequencies used for upstream communications and limit the upstream power to a fixed predetermined power level. However, such filters reduce flexibility because filters provided by a manufacturer are typically designed based on worst case scenarios. Flexibility may be provided by allowing a modem user or technician to change the filter power output, but this would require the user or technician to access the internal components of the modem, which may result in reduced efficiency or lifespan of the modem."

From

http://www.patentstorm.us/patents/6690768/description.html

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!