diff --git a/src/subprocess_util/chunked_transfer/active_send/common.py b/src/subprocess_util/chunked_transfer/active_send/common.py
new file mode 100644
index 0000000..6833cef
--- /dev/null
+++ b/src/subprocess_util/chunked_transfer/active_send/common.py
@@ -0,0 +1,10 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+from enum import Enum
+
+
+class NextChunkEnum(Enum):
+    OK_BINARY = b'OK\n'
+    OK_STR = 'OK\n'
+    EOF_BINARY = b'EOF\n'
+    EOF_STR = 'EOF\n'
diff --git a/src/subprocess_util/chunked_transfer/active_send/exec_receive_chunks_passive.py b/src/subprocess_util/chunked_transfer/active_send/exec_receive_chunks_passive.py
index 4493f59..0f6481b 100644
--- a/src/subprocess_util/chunked_transfer/active_send/exec_receive_chunks_passive.py
+++ b/src/subprocess_util/chunked_transfer/active_send/exec_receive_chunks_passive.py
@@ -2,6 +2,7 @@ import socket
 from pathlib import Path
 from queue import Queue
 
+from subprocess_util.chunked_transfer.active_send.common import NextChunkEnum
 from subprocess_util.exec_consume_chunks import execute_consume_chunks
 from subprocess_util.unix_sock_input import accept_loop_until_message
 
@@ -23,11 +24,11 @@ def exec_receive_chunks_passive(
         sock.listen(1)
 
         chunk_no = 1
-        messages = [b'OK\n', b'EOF\n']
+        messages: list[bytes] = [NextChunkEnum.OK_BINARY.value, NextChunkEnum.EOF_BINARY.value]
         while True:
             msg = accept_loop_until_message(sock, messages)
 
-            last_chunk = msg == b'EOF\n'
+            last_chunk = msg == NextChunkEnum.EOF_BINARY.value
             target_chunk_path = get_target_chunk_path(chunk_no)
             queue_put((target_chunk_path, last_chunk))
 
diff --git a/src/subprocess_util/chunked_transfer/active_send/exec_send_chunks_active.py b/src/subprocess_util/chunked_transfer/active_send/exec_send_chunks_active.py
index 871c4b6..5f91f9f 100644
--- a/src/subprocess_util/chunked_transfer/active_send/exec_send_chunks_active.py
+++ b/src/subprocess_util/chunked_transfer/active_send/exec_send_chunks_active.py
@@ -1,6 +1,7 @@
 import shlex
 from pathlib import Path
 
+from subprocess_util.chunked_transfer.active_send.common import NextChunkEnum
 from subprocess_util.exec_produce_chunks import execute_produce_chunks
 from subprocess_util.repeat import repeat_until_successful
 
@@ -26,14 +27,14 @@ def exec_send_chunks_active(
         usr_confirmation_socket = source_chunk_path.parent.joinpath(f'{chunk_no}.SOCKET')
         target_socket = target_chunk_dir.joinpath('SOCKET')
 
-        message = 'EOF' if last_chunk else 'OK'
+        message: str = NextChunkEnum.EOF_STR.value if last_chunk else NextChunkEnum.OK_STR.value
 
         rsync_cmd = ['rsync',
                      str(source_chunk_path),
                      f'{ssh_target}:{str(target_chunk_path)}']
         inform_cmd = ['ssh',
                       ssh_target,
-                      f'echo {message} | nc -U {shlex.quote(str(target_socket))}']
+                      f"printf '{message}' | nc -U {shlex.quote(str(target_socket))}"]
 
         repeat_until_successful(rsync_cmd, usr_confirmation_socket)
         # Delete local chunk after it has been transferred.