We had some old PBX-s and some place where use 4-5 analog phone line instead off a small pbx with a digital phone. We changed that for definitys and the digital phone users lament they audible less volume , then earlyer. And they have right! And the analog ext. has no propblem. The digit ( 64xx or 84xx) ext users have to put the microphone in to theirs mouth, then they has good audible. After this I called some other company, which have Definity, and if a digit ext pick up the phones I heard this low volume. The avaya service try to do something, ( setting 64xx 84xx parameter), but that was unsuccesfull. Our PBXs have ISDN 30 trunks. What do You think about it?