We live in an old building with old phone lines, but DSL seems to work well. However, it occasionally has these fits where the DSL modem simply cannot/will not connect to the DSL line - no amount of restarting (both the modem and the computer), running diagnostics, etc. will make it connect.
But the second I pick up the phone and dial a number (usually the tech support number!), the line immediately connects. I can even hear it on the line - that familiar high-pitched sound as it connects.
You can actually hear your DSL modem connecting on the line???
The technology is designed so that your voice line and DSL use different bands and can’t “hear” each other (unless it’s some exotic new DSL that I don’t know about). That’s why you use filters on every phone but not the DSL modem.
I’m using the filters, and properly. The sound of the DSL isn’t really “audible” - it’s more of a background thing, akin to any other line noise. It doesn’t interfere with conversation.
When your DSL is not working, do you have “sync?” That is to say, is there an indicator on the modem that says an ADSL signal is detected? This is often an LED labled “DSL”, “ADSL”, or “Sync”, and is usually a solid green when connected.
Sorry, I should have clarified - My DSL light flashes red, meaning “cannot connect to the DSL line.” The second I dial a number with the phone, that line turns green and I can access the internet.
My WAG: You’ve got a bad connection somewhere in your phone system. The connection is poor enough that you’re getting a somewhat non-conductive layer forming between two pieces of metal. When you pick up your phone, a DC current flows through the connection and punches through the spotty non-conductive part, restoring the data path for the higher frequency DSL signal.
Never heard that one before. If you have interference in your line, some line cards will go into a loop trying to re-establish sync until they finally give up. Your phone line also goes through that same card, so it could possibly interpret an active dial tone as a trigger to re-establish sync again.
In cases like this it usually turns out to be the modem, wiring, or line card. But tech support should know that. If you use the phrase “intermittent sync” then it should make a light bulb go off, so they can narrow it down more quickly.