My internet, er, filter?

I couldn’t get online earlier tonight, even after Charter’s brilliant technical assistance – consisting of having me unplug and then plug back in the modem. Then I noticed there was some kind of filter-looking device between the coax cable and the modem. I took it out and screwed the coax straight into the box. Immediate re-connection, and ability to post this thread ensued.

What is it? It’s labeled Arcom ARSA50-3. I found what I assume is the manufacturer’s website, and there is no reference.

Any clues what it does, and whether there is any reason for me to replace it, would be appreciated.

I don’t really want to talk to Charter about it yet, in case I’ve violated some goofy rule. Note: there is no warning sign visible like “do not remove under penalty of law”, which even my pillows still have.

Could it be some kind of fuse/breaker?

It’s a noise filter.

Here’s a thread about it in another forum.

Hey it worked for Kyle on South Park when the Internet went down.
(to see the hilarious episode if you don’t know what I’m talking about, click here, then season 12, episode entitled “Over Logging”)

I remember something about filters being used when stealing analog cable. It prevented the cable company from resetting the compromised cable box.