Digital phone compatibility

[RV482]

HI!

We have an existing TDA200 and planning on retiring it, will the digital phones, KX-T7600 series be compatible with the NS300 or TDE IP-PBX?

Also, I was told that the NS300 has a maximum of 128 capacity, we would require 150 analog and 50 digital, will the NS300 be able to expand with this config. we are more on the NS300 to fit the 19" rack.

Thanks!