Additionally, linking 2 MICS together with E&M will not provide calling station ID between the 2 systems.
If you have ext 2000, 2014, and 2025 on 1 MICS, and 3000, 3010, and 3020 on the second, calling from 2000 to 2014 will show the calling party. Calling from 2000 to 3000 will not. Likewise, calling from 3000 to 3010 will show the calling party, but from 3000 to 2014 will not