diff --git a/src/ecss/tc.rs b/src/ecss/tc.rs
index a537151..3c1c25a 100644
--- a/src/ecss/tc.rs
+++ b/src/ecss/tc.rs
@@ -213,7 +213,7 @@ impl PusTcSecondaryHeader {
 
 pub mod legacy_tc {
     use crate::ecss::tc::{
-        zc, GenericPusTcSecondaryHeader, PusTcSecondaryHeader, ACK_ALL,
+        zc, GenericPusTcSecondaryHeader, IsPusTelecommand, PusTcSecondaryHeader, ACK_ALL,
         PUC_TC_SECONDARY_HEADER_LEN, PUS_TC_MIN_LEN_WITHOUT_APP_DATA,
     };
     use crate::ecss::{
@@ -524,6 +524,8 @@ pub mod legacy_tc {
             fn ack_flags(&self) -> u8;
         });
     }
+
+    impl IsPusTelecommand for PusTc<'_> {}
 }
 
 /// This class can be used to create PUS C telecommand packet. It is the primary data structure to
diff --git a/src/ecss/tm.rs b/src/ecss/tm.rs
index 78b41f7..872ab11 100644
--- a/src/ecss/tm.rs
+++ b/src/ecss/tm.rs
@@ -196,8 +196,8 @@ impl<'slice> TryFrom<zc::PusTmSecHeader<'slice>> for PusTmSecondaryHeader<'slice
 
 pub mod legacy_tm {
     use crate::ecss::tm::{
-        zc, GenericPusTmSecondaryHeader, PusTmSecondaryHeader, PUC_TM_MIN_SEC_HEADER_LEN,
-        PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
+        zc, GenericPusTmSecondaryHeader, IsPusTelemetry, PusTmSecondaryHeader,
+        PUC_TM_MIN_SEC_HEADER_LEN, PUS_TM_MIN_LEN_WITHOUT_SOURCE_DATA,
     };
     use crate::ecss::PusVersion;
     use crate::ecss::{
@@ -517,6 +517,8 @@ pub mod legacy_tm {
             fn sc_time_ref_status(&self) -> u8;
         });
     }
+
+    impl IsPusTelemetry for PusTm<'_> {}
 }
 
 /// This class models the PUS C telemetry packet. It is the primary data structure to generate the