diff --git a/satrs-core/src/lib.rs b/satrs-core/src/lib.rs
index d1b25d2..fd456c3 100644
--- a/satrs-core/src/lib.rs
+++ b/satrs-core/src/lib.rs
@@ -26,6 +26,7 @@ pub mod events;
 pub mod executable;
 pub mod hal;
 pub mod hk;
+pub mod mode;
 pub mod objects;
 pub mod params;
 #[cfg(feature = "alloc")]
diff --git a/satrs-core/src/mode.rs b/satrs-core/src/mode.rs
index e69de29..00e534d 100644
--- a/satrs-core/src/mode.rs
+++ b/satrs-core/src/mode.rs
@@ -0,0 +1,25 @@
+use crate::tmtc::TargetId;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct ModePair {
+    mode: u32,
+    submode: u16,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct ModeCommand {
+    address: TargetId,
+    mode: ModePair,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum ModeRequest {
+    SetMode(ModeCommand),
+    ReadMode(TargetId),
+    AnnounceMode(TargetId),
+    AnnounceModeRecursive(TargetId),
+}
diff --git a/satrs-core/src/tmtc/mod.rs b/satrs-core/src/tmtc/mod.rs
index f410eea..c2a0aa6 100644
--- a/satrs-core/src/tmtc/mod.rs
+++ b/satrs-core/src/tmtc/mod.rs
@@ -23,10 +23,12 @@ pub use ccsds_distrib::{CcsdsDistributor, CcsdsError, CcsdsPacketHandler};
 #[cfg(feature = "alloc")]
 pub use pus_distrib::{PusDistributor, PusServiceProvider};
 
+pub type TargetId = u32;
+
 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct AddressableId {
-    pub target_id: u32,
+    pub target_id: TargetId,
     pub unique_id: u32,
 }