Line 1 doesnt work
The 1st line either cannot be picked up (on one of the phones) or you pick up and there is no dial tone. It is just static air. The other lines and extensions work just fine.
Lands Phones - Quality AT&T - AT&T 1070 - 1070 Corded Four-Line Expandable Telephone,...
Answers & Comments
Please replace the line set cords and splitter if your using one, do not plug a dsl filter on the jack the phones are on, if this doesn't work call a phone man with phone company training only, make sure nothing is crossed in the NID /dmarc box blessings!