details: got new Fusion service and worked well for a week. Then started getting intermittent sync issues (modem sync repeatedly - yellow light blinks on ZTE modem). I noticed static on voice line. After trying to see if using corded phone makes difference, or trying to connect modem only without phone to isolate issue, I called support and they ran line tests (passed fine although at slightly slower speed than before) said it may be related to a big rainfall the night before and asked me to watch for a few days and call again if problems persists. After a week of intermittent issues (and no rain), it got worse. Sonic sent new modem, which I connected but got sync issues again and had to reset modem to get it to reconnect. New modem came with a different splitter, so tried that, and problem went away. Voice line has less static too. So far, OK for 2 days.
So the white SP-206 splitter seems bad. The beige Shuttle splitter with two jacks and one short cord seems to be the solution. SP-206 has three jacks and no cord.
My question: I realize DSL filters go bad, but is this common and should I keep a few new ones ready or to replace periodically? If I buy retail, do you recommend another good one (maybe At&t store' or Radio Shack).
I guess this is a case of a weakest link in the chain making system fail. I was prepared to blame house wiring but dreaded that. Neighbors in same apartment had good DSL (via AT&T) so I thought line to CO was good.