Actually, bet dollars to donuts, the protector is bad in the NID which is located on the TELCO side. Having DSL and no dial tone isn't strange at all.
The transformer in the DSL filter/splitter isolates the DC required by the phone, but not DSL.
Do you have a voltmeter?
Just tell the telco that the problem occurs when usig the test jack at the NID. Your not supposed to replace the protector. Some protectors are better than others for DSL.
While your at it, talk to the tech and see if he will replace the 1/2 ringer in the NID with a "no electronics module with an "auto-jack.
They also may install a DSL filter for free for you, but you may have to do the inside wiring later. You may have to ask them to upgrade the cable entering the house so an extra pair is available.
A protector by Bournes and the above mods will definitely improve your DSL performance. My DSL tests at the limits of service and the tech described the line as pristine.
All wires in the home are QUAD cable with non-home runs and about 10 locations. There are even 4 prong and modular jacks and sometimes multiple jacks at the location. An impossible install with filters, but pristine with a splitter.
The telco needs to solve it. This guy http://www.bourns.com/data/global/pd...30S%29revB.pdf
Actually, if you do a DSL speedtest using www.speakeasy.net
performace will be crappy.