diff --git a/meshtastic/ble_interface.py b/meshtastic/ble_interface.py
index c4b542f..28d55cd 100644
--- a/meshtastic/ble_interface.py
+++ b/meshtastic/ble_interface.py
@@ -7,6 +7,8 @@ import asyncio
 from threading import Thread, Event
 from bleak import BleakScanner, BleakClient
 
+from typing import Optional
+
 from meshtastic.mesh_interface import MeshInterface
 from meshtastic.util import our_exit
 
@@ -30,7 +32,7 @@ class BLEInterface(MeshInterface):
         MESH = False
 
 
-    def __init__(self, address, noProto = False, debugOut = None):
+    def __init__(self, address: Optional[str], noProto: bool = False, debugOut = None):
         self.state = BLEInterface.BLEState()
 
         if not address:
diff --git a/meshtastic/serial_interface.py b/meshtastic/serial_interface.py
index 0ae68aa..e3c3a48 100644
--- a/meshtastic/serial_interface.py
+++ b/meshtastic/serial_interface.py
@@ -6,6 +6,8 @@ import time
 
 import serial # type: ignore[import-untyped]
 
+from typing import Optional
+
 import meshtastic.util
 from meshtastic.stream_interface import StreamInterface
 
@@ -16,7 +18,7 @@ if platform.system() != "Windows":
 class SerialInterface(StreamInterface):
     """Interface class for meshtastic devices over a serial link"""
 
-    def __init__(self, devPath=None, debugOut=None, noProto=False, connectNow=True):
+    def __init__(self, devPath: Optional[str]=None, debugOut=None, noProto=False, connectNow=True):
         """Constructor, opens a connection to a specified serial port, or if unspecified try to
         find one Meshtastic device by probing
 
@@ -26,7 +28,7 @@ class SerialInterface(StreamInterface):
         """
         self.noProto = noProto
 
-        self.devPath = devPath
+        self.devPath: Optional[str] = devPath
 
         if self.devPath is None:
             ports = meshtastic.util.findPorts(True)
diff --git a/meshtastic/util.py b/meshtastic/util.py
index f9e1b1e..bc24e33 100644
--- a/meshtastic/util.py
+++ b/meshtastic/util.py
@@ -11,7 +11,7 @@ import threading
 import time
 import traceback
 from queue import Queue
-from typing import Union
+from typing import List, NoReturn, Union
 
 from google.protobuf.json_format import MessageToJson
 
@@ -122,7 +122,7 @@ def catchAndIgnore(reason, closure):
         logging.error(f"Exception thrown in {reason}: {ex}")
 
 
-def findPorts(eliminate_duplicates=False):
+def findPorts(eliminate_duplicates: bool=False) -> List[str]:
     """Find all ports that might have meshtastic devices
        eliminate_duplicates will run the eliminate_duplicate_port() on the collection
 
@@ -263,7 +263,7 @@ class DeferredExecution:
                 print(traceback.format_exc())
 
 
-def our_exit(message, return_value=1):
+def our_exit(message, return_value=1) -> NoReturn:
     """Print the message and return a value.
     return_value defaults to 1 (non-successful)
     """