Why wouldn't a standard feature such as call trace not work with FiOS? Regardless of the transport medium it'd still be going back to the same switch in the end and that's where your feature sets are if I'm not mistaken.

That's very interesting to me. It's not stated that the feature doesn't work with FiOS either:

https://www22.verizon.com/ForYourHome/CustomerSupport/Guides/UG_VAS_West.pdf


--Matt