Is there anywhere hidden away in the HG612 firmware to report an overall attenuation value.

I know it has been discussed previously, but as the ECI can do it.............?

The attenuation values are only available from the kernel driver on an individual subcarrier basis. So the calculation of the overall attenuation for a band or bands is a mathematical function performed by a userspace tool.

In the Broadcoms, a tool called

xdslcmd calculates the aggregate attenuation value for each frequency band. In theory we could also calculate the overall attenuation value for all DS bands, just as the JDSU and Exfo devices do.

**EDIT:**The equation for calculating an aggregate attenuation value is hidden in plain sight... in the

*G992.3 Recommendations* [1]

The average attenuation for a line, a band, a channel or an aggregate of channels is calculated from the linear magnitude function

Hlin(f) for each tone, rather than from the logarithmic values from

Hlog(f).

However, we can convert

Hlog(f) values to

Hlin(f) magnitude values using antilogs.

The average attenuation for a channel is then given by the following equation, where

*NSC* is the Number of Sub-Carriers or DMTs utilised by the channel,

*i* is the subcarrier index and

*Δf* is the subcarrier spacing (4.3125kHz for most xDSL standards):

Attached is a ZIP containing sample

Hlog data from

*Bald_Eagle*'s line, and a small C program that uses the above equation to calculate an aggregate attenuation value for each downstream frequency band using that

Hlog data.

cheers, a

[1]

http://huaweihg612hacking.wordpress.com/2011/10/01/measuring-line-characteristics-on-the-huawei/