@Alvaphonepro - Figured out that 1 out of 12 extensions does have some kind of short. Have to check a 300' run that goes underground . . . praying the problem is at a terminator block.
@Carl - the feature manual (FM) pg 21 1.1.9 says . . . "a busy extension (i.e., an extension that is ringing or having a conversation), . . . so you're right it appears to be a feature. Tried FWD, DND, Delayed Ring all worked as expected given FM explaination.
After clearing all of the memory I started to add KX-T7030 phones to the system. First extension, X101, each DDS would light up with an incoming call per the FM.
The moment I programmed one button at a station, say x103, the DDS buttons on the other stations (X101, X102) representing X103 ceased to light when a CO rings but operated just like my old 616 (ie light on transfer, intercom, off-hook but not on incoming CO ring). Great . . . that is what I need!
Extension with SLT, fax, KX-T7020's or no phone still have the problem/feature of DDS lighting on incoming CO ring (work around - use delay ring).
I am unable to get any KX-T7020's to program or operate at all. Are these phones compatible with the KX-TA824? My supplier's techie, who has been helpful today, says yes; my experience so far - says no (work around - buy some 7700's)
Next step is to dive into the software programming. I think I've exhausted the programming from a phone (really use to the 616). Any particular areas covering DDS and BLFs fot SLT that I should focus on?
BTW, this is a relatively simple install. It is in a private home that is rented during the summers. So a way to answer 2 COs or intercom from about 12 locations, a fax and a simple answering machine. The only thing the 616 needed (or, actually, I wanted) was CID and a few more extensions.
I had great luck with the KX-T61610 for 20+ years in this location. Hoping the 824 is as durable and trouble free.
Thx
