High Pass Filter DSL FAQ | DSLReports.com, ISP Information

High Pass Filter

A high pass filter is a tiny device attached to your cable line to block anything below a certain frequency. A 50MHz HPF would block anything below 50Mhz.

This can be used to prevent very low frequency interference, or to block unauthorized cable modems from attempting to contact the head end, or even to remove TV service from your line while leaving HSD up.

For example, if your cable modem is to talk back to your provider at 29.5Mhz, and this HPF was on your line, your provider would never hear it, because it's below 50Mhz.

If you are having interference on your TV channels while online, try putting a HPF on the TV lines at the splitter. Do NOT filter your cable modem line or you will kill your connection.

I've seen HPFs that run from 50MHz up to 550Mhz.

got feedback?

This article refers to cable internet but the article itself is categorized under a DSL FAQ. Shouldn't the article contain ADSL, not coax, filter information?

2009-03-06 01:25:26

I just have to thank you, I have doing a little research because the cable company turn off my service out of the blue then came out and said they had to hook one of those (EHP, EMHP Highpass Filters 50.0) on my line in the house because my TV was interfering with their system. First real info that make sense on your site. Still don't believe my TV is causing issues with their system, they said it was causing issues with their internet system. BS I am sure, guessing they just wanted to block some channels or something.

2009-09-27 05:57:09

by KeysCapt

Also read About DSL for lots more information

All FAQs » DSL FAQ » 1.05 Broadband Terminology

High Pass Filter