From what I can tell, I70 is just loudspeaker (paging port) page. I*70 is loudspeaker and phones paging. I've noticed that when using a SLT (I'm talking about a regular old phone call) when you hang up it takes about a second for the associated line light to go out on a system phone. Obviously it can't disconnect the call as soon as you go on hook or things like hook flash wouldn't work to put calls on hold and stuff like that. (Still talking about using the SLT here.) It's during this brief time right after going on hook before the system cuts the line off -this time the paging port instead of a co line- that I get this screeching tone. A system phone hangs up right away since there's no need for hook flash, so they don't exhibit this odd behavior. I'm wondering if I've got something programmed wrong, a faulty processor, or something else I've overlooked. I've tried unplugging EVERYTHING from the modules thinking maybe just one phone somewhere was the culprit, I've tried to narrow it down as much as I can and this is where I'm at. I'm so used to dialing I*70 to make a page that I want to make it work if I can. If I have to just add everything to group one and dial I*71, then so be it, but I like to try to fix problems rather than band-aid them.