I believe the tri-mode is: 1) 900MHz analog 2) 900MHz digital 3) 1800MHz digital . Not sure but I think I read that somewhere.
Also, I believe all of the carriers received permission from the FCC to turn of the analog towers as needed earlier this year but I believe there are still some analog towers active in rural areas.
Mel
Mel Linville
US Army MSG (Ret)
2020 Ram 2500 Hemi and shopping for a cheap, used, small 5th wheel