diff --git a/CHANGELOG.md b/CHANGELOG.md
index 92f6090..eccc14c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,18 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 # [unreleased]
 
+## Added
+
+- `num_enum` dependency to avoid boilerplate code for primtive to enum conversions, for example
+  for the PUS subservices.
+- `ecss.event` module containing a `Subservice` enum.
+- `ecss.verification` module containing a `Subservice` enum.
+- `ecss.scheduling` module containing a `Subservice` enum and some other helper enumerations.
+
+## Changed
+
+- Added missing Service IDs to `ecss.PusServiceId` and marked in `#[non_exhaustive]`.
+
 # [v0.5.2] 2023-01-26
 
 ## Added
diff --git a/Cargo.toml b/Cargo.toml
index 035424c..8e9e715 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,7 @@ categories = ["aerospace", "aerospace::space-protocols", "no-std", "hardware-sup
 zerocopy = "0.6"
 crc = "3"
 delegate = ">=0.8, <0.10"
+num_enum = "0.5"
 
 [dependencies.serde]
 version = "1"
diff --git a/src/ecss/event.rs b/src/ecss/event.rs
new file mode 100644
index 0000000..622ab5b
--- /dev/null
+++ b/src/ecss/event.rs
@@ -0,0 +1,43 @@
+//! PUS Service 5 Events
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+use num_enum::{IntoPrimitive, TryFromPrimitive};
+
+#[derive(Debug, Eq, PartialEq, Copy, Clone, IntoPrimitive, TryFromPrimitive)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(u8)]
+pub enum Subservice {
+    TmInfoReport = 1,
+    TmLowSeverityReport = 2,
+    TmMediumSeverityReport = 3,
+    TmHighSeverityReport = 4,
+    TcEnableEventGeneration = 5,
+    TcDisableEventGeneration = 6,
+    TcReportDisabledList = 7,
+    TmDisabledEventsReport = 8,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_conv_into_u8() {
+        let subservice: u8 = Subservice::TmLowSeverityReport.into();
+        assert_eq!(subservice, 2);
+    }
+
+    #[test]
+    fn test_conv_from_u8() {
+        let subservice: Subservice = 2.try_into().unwrap();
+        assert_eq!(subservice, Subservice::TmLowSeverityReport);
+    }
+
+    #[test]
+    fn test_conv_fails() {
+        let conversion = Subservice::try_from(9);
+        assert!(conversion.is_err());
+        let err = conversion.unwrap_err();
+        assert_eq!(err.number, 9);
+    }
+}
diff --git a/src/ecss/mod.rs b/src/ecss/mod.rs
index dbde721..7ad259c 100644
--- a/src/ecss/mod.rs
+++ b/src/ecss/mod.rs
@@ -7,12 +7,15 @@ use crate::{ByteConversionError, CcsdsPacket, SizeMissmatch};
 use core::fmt::{Debug, Display, Formatter};
 use core::mem::size_of;
 use crc::{Crc, CRC_16_IBM_3740};
+use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 #[cfg(feature = "std")]
 use std::error::Error;
 
 pub mod scheduling;
+pub mod event;
+pub mod verification;
 
 pub type CrcType = u16;
 
@@ -20,21 +23,51 @@ pub type CrcType = u16;
 pub const CRC_CCITT_FALSE: Crc<u16> = Crc::<u16>::new(&CRC_16_IBM_3740);
 pub const CCSDS_HEADER_LEN: usize = size_of::<crate::zc::SpHeader>();
 
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(u8)]
+#[non_exhaustive]
 pub enum PusServiceId {
     /// Service 1
     Verification = 1,
+    /// Service 2
+    DeviceAccess = 2,
     /// Service 3
     Housekeeping = 3,
+    /// Service 4
+    ParameterStatistics = 4,
     /// Service 5
     Event = 5,
+    /// Service 6
+    MemoryManagement = 6,
     /// Service 8
     Action = 8,
+    /// Service 9
+    TimeManagement = 9,
     /// Service 11
     Scheduling = 11,
+    /// Service 12
+    OnBoardMonitoring = 12,
+    /// Service 13
+    LargePacketTransfer = 13,
+    /// Service 14
+    RealTimeForwardingControl = 14,
+    /// Service 15
+    StorageAndRetrival = 15,
     /// Service 17
     Test = 17,
+    /// Service 18
+    OpsAndProcedures = 18,
+    /// Service 19
+    EventAction = 19,
+    /// Service 20
+    Parameter = 20,
+    /// Service 21
+    RequestSequencing = 21,
+    /// Service 22
+    PositionBasedScheduling = 22,
+    /// Service 23
+    FileManagement = 23
 }
 
 /// All PUS versions. Only PUS C is supported by this library.
diff --git a/src/ecss/scheduling.rs b/src/ecss/scheduling.rs
index 09cb4f6..e9f3e1b 100644
--- a/src/ecss/scheduling.rs
+++ b/src/ecss/scheduling.rs
@@ -1,9 +1,11 @@
 //! PUS Service 11 Scheduling
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
+use num_enum::{IntoPrimitive, TryFromPrimitive};
 
-#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone, IntoPrimitive, TryFromPrimitive)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(u8)]
 pub enum Subservice {
     // Core subservices
     TcEnableScheduling = 1,
@@ -73,7 +75,7 @@ pub enum TimeWindowType {
 
 #[cfg(test)]
 mod tests {
-    use crate::ecss::scheduling::SchedStatus;
+    use super::*;
 
     #[test]
     fn test_bool_conv_0() {
@@ -88,4 +90,16 @@ mod tests {
         let status: SchedStatus = enabled.into();
         assert_eq!(status, SchedStatus::Disabled)
     }
+
+    #[test]
+    fn test_conv_into_u8() {
+        let subservice: u8 = Subservice::TcCreateScheduleGroup.into();
+        assert_eq!(subservice, 22);
+    }
+
+    #[test]
+    fn test_conv_from_u8() {
+        let subservice: Subservice = 22u8.try_into().unwrap();
+        assert_eq!(subservice, Subservice::TcCreateScheduleGroup);
+    }
 }
diff --git a/src/ecss/verification.rs b/src/ecss/verification.rs
new file mode 100644
index 0000000..9c0b709
--- /dev/null
+++ b/src/ecss/verification.rs
@@ -0,0 +1,35 @@
+//! PUS Service 1 Verification
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+use num_enum::{IntoPrimitive, TryFromPrimitive};
+
+#[derive(Debug, Eq, PartialEq, Copy, Clone, IntoPrimitive, TryFromPrimitive)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(u8)]
+pub enum Subservice {
+    TmAcceptanceSuccess = 1,
+    TmAcceptanceFailure = 2,
+    TmStartSuccess = 3,
+    TmStartFailure = 4,
+    TmStepSuccess = 5,
+    TmStepFailure = 6,
+    TmCompletionSuccess = 7,
+    TmCompletionFailure = 8,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_conv_into_u8() {
+        let subservice: u8 = Subservice::TmCompletionSuccess.into();
+        assert_eq!(subservice, 7);
+    }
+
+    #[test]
+    fn test_conv_from_u8() {
+        let subservice: Subservice = 7.try_into().unwrap();
+        assert_eq!(subservice, Subservice::TmCompletionSuccess);
+    }
+}
\ No newline at end of file