Thread: Faulty ADSL Filter Injects Noise into Line Side

Faulty ADSL Filter Injects Noise into Line Side

I just changed from cable internet to ADSL2+ .

Three phones plus modem in the home.

Pulled my hair out trying to reduce what I thought was ADSL noise getting into my phones.

Eventually found that a D-Link C10245E splitter filter on one phone was injecting noise back down the line into other phones, whilst still working as an ADSL filter on the fitted phone!

The noise sounded quite like ADSL noise, only slightly harsher and not interrupted, and could not be heard on the fitted phone, only on the other phones.

Opened up the filter expecting to see passive components; there are four active devices, (and about 50 other components on the board)!

Lessons - With faults of this type, always do an "Isolation Test" meticulously, and expect the unexpected.

Oh, and by the way, if you have ADSL2+, make sure that you use quality ADSL2 filters (not ADSL filters), as the cheapies will just give you trouble, and are a waste of money. (Yes- I know the C10 is ADSL only).

cheerio, mike