cellio: (avatar-face)
Monica ([personal profile] cellio) wrote2004-11-26 03:44 pm
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modem weirdness

The fine folks at Telerama lent us a modem with which to test. (We've been having random short-term network lossage.) The test modem, however, is unhappy in new and novel ways.

With the test modem, pings and SSH connections get through just fine, but web browsing isn't happening. (I saw one page get to "transferring..." before failing, but most sites timed out at "resolving host". Reminder: other uses of name service were fine.) I cleared the cache and restarted the browser, which didn't make a difference. Dani reported the same behavior with a different browser on a different machine. Restoring the original modem made the problem go away.

So that was oddity #1. Oddity #2 presented itself when I picked up the phone to call tech support about oddity #1 -- and found a very noisy line. After switching to my cell phone, I talked to someone who suggested that the noise is due to a lack of filtering on the phone line and he has no clue why the selective network service would be happening. But the old modem doesn't produce noise on the line, and all I did was swap the cables to the new modem and turn it on. I definitely didn't change any configuration on our phone lines.

Could it be that some modems have this filtering built-in and others don't? That seems weird to me, as the person I talked to seemed to be saying that the filtering has to be done to all jacks, and I certainly got the noise on a different jack than the one supporting the modem (which is consistent with that). I know that BellAtlantic came in and did something to our phone line before installing DSL 5+ years ago, but it was a change at the box and not at the jacks.

Both modems are Westell, though of different vintages.

I am now officially perplexed.

[identity profile] nsingman.livejournal.com 2004-11-26 09:06 pm (UTC)(link)
We've had DSL for several years (through Verizon and Covad), and the only line filters I know about are the physical filters that are supposed to be placed between your analog telephonic devices (handsets, fax machines, etc.) and the wall jacks.