hi all..new to this forum and the telecom business..glad you're here.there's an existing install with nec electra pro level 1 system.there was 1 dtu 16 on the system, the other 4 were etw 8. the owner purchased 4 16 dtu's to replace the etw 8's..when they didn't work they asked me to check into it. thru the magic of this forum, i found out about switching the jack leads which made the phones work, but with a few minor glitches. 1 phones' "mic" light is on, another has the "answer" light on. are these phones just incompatible with their system?it's a restaurant and they live by their phones. thanks in advance.