There are a total of 10 terminals available in Halo CEA, available on any difficulty as follows:
[
0:09] - Terminal 1 - Mission: The Pillar of Autumn
[
0:27] - Terminal 2 - Mission: Halo
[
1:20] - Terminal 3 - Mission: The Truth and Reconciliation
[
1:43] - Terminal 4 - Mission: The Silent Cartographer
[
2:09] - Terminal 5 - Mission: Assault on the Control Room
[
2:56] - Terminal 6 - Mission: Guilty Spark
[
3:31] - Terminal 7 - Mission: The Library
[
4:22] - Terminal 8 - Mission: Two Betrayals
[
4:43] - Terminal 9 - Mission: Keyes
[
5:09] - Terminal 10 - Mission: The Maw
Collecting the above skulls will also unlock the following achievements: