Note that in 10/100 mode on older systems (that meet the minimums) they will not pull matching firmware to the system and will use the Out of Box firmware. If the phones are used in a newer system, say an MCD 6.0 or Mitel 5000 6.0 system, and then you attempt to put them on an older system, they will NOT work anymore except on a system that completely supports them. Trust me on this, I learned the hard way.
In the drop down of the User phone type, you just select 5330.