That's funny that you guys haven't experienced the humm, I've had it on every DSX I've touched (about 8), once it's grounded the humm is gone but there is still alot of sidetone.
They have gotten better with software upgrades, we really like the system, my boss likes it because it's inexpensive and I like it cuz it's easy to program and use with lots of features. Hopefully they've started shipping with the B trunk cards.
