What is the consensus on using Norstar phones on an IP office? Can we be all Norstar phones or must we have some Avaya phones? Is this a feature that's still supported? Also do the Norstar phones function fully or in some limited fashion?

take a look at you tube they have videos on Norstar phone on IP office

DS 16B/30B modules can be upgraded to run either or. But it is all one, or the other. But i could have 2 modules, one running Avaya, one running Nortel.

Be wary of which "M" series sets you want to reuse, as not all of them will work.

See the docs here to help determine which phones can be reused...and which features are compatible.

it is from a few years ago, before IPO got park n page, and MADN....

https://avaya.sharefile.com/d-s50dd2c21f3e422cb