diff --git a/internal/devices/flexradio/types.go b/internal/devices/flexradio/types.go
index 96b9a09..8af11d4 100644
--- a/internal/devices/flexradio/types.go
+++ b/internal/devices/flexradio/types.go
@@ -14,3 +14,12 @@ type Status struct {
 	NumSlices    int     `json:"num_slices"`    // From info command
 	ActiveSlices int     `json:"active_slices"` // Count of active slices
 }
+
+// InterlockState represents possible interlock states
+const (
+	InterlockStateReady          = "READY"
+	InterlockStateNotReady       = "NOT_READY"
+	InterlockStatePTTRequested   = "PTT_REQUESTED"
+	InterlockStateTransmitting   = "TRANSMITTING"
+	InterlockStateUnkeyRequested = "UNKEY_REQUESTED"
+)