diff --git a/src/engineio/async_client.py b/src/engineio/async_client.py
index 5e5980f..07fe2df 100644
--- a/src/engineio/async_client.py
+++ b/src/engineio/async_client.py
@@ -71,7 +71,6 @@ class AsyncClient(base_client.BaseClient):
                                     arguments passed to
                                     ``aiohttp.ws_connect()``.
     """
-
     def is_asyncio_based(self):
         return True
 
diff --git a/src/engineio/base_client.py b/src/engineio/base_client.py
index 5b2eac1..6381be2 100644
--- a/src/engineio/base_client.py
+++ b/src/engineio/base_client.py
@@ -1,4 +1,6 @@
 import logging
+import signal
+import threading
 import time
 import urllib
 from . import packet
@@ -7,12 +9,35 @@
 connected_clients = []
 
 
+def signal_handler(sig, frame):
+    """SIGINT handler.
+
+    Disconnect all active clients and then invoke the original signal handler.
+    """
+    for client in connected_clients[:]:
+        if not client.is_asyncio_based():
+            client.disconnect()
+    if callable(original_signal_handler):
+        return original_signal_handler(sig, frame)
+    else:  # pragma: no cover
+        # Handle case where no original SIGINT handler was present.
+        return signal.default_int_handler(sig, frame)
+
+
+original_signal_handler = None
+
+
 class BaseClient:
     event_names = ['connect', 'disconnect', 'message']
 
     def __init__(self, logger=False, json=None, request_timeout=5,
                  http_session=None, ssl_verify=True, handle_sigint=True,
                  websocket_extra_options=None):
+        global original_signal_handler
+        if handle_sigint and original_signal_handler is None and \
+                threading.current_thread() == threading.main_thread():
+            original_signal_handler = signal.signal(signal.SIGINT,
+                                                    signal_handler)
         self.handlers = {}
         self.base_url = None
         self.transports = None
diff --git a/src/engineio/client.py b/src/engineio/client.py
index d387b62..51207a1 100644
--- a/src/engineio/client.py
+++ b/src/engineio/client.py
@@ -2,7 +2,6 @@
 from engineio.json import JSONDecodeError
 import logging
 import queue
-import signal
 import ssl
 import threading
 import time
@@ -24,24 +23,6 @@
 default_logger = logging.getLogger('engineio.client')
 
 
-def signal_handler(sig, frame):
-    """SIGINT handler.
-
-    Disconnect all active clients and then invoke the original signal handler.
-    """
-    for client in base_client.connected_clients[:]:
-        if not client.is_asyncio_based():
-            client.disconnect()
-    if callable(original_signal_handler):
-        return original_signal_handler(sig, frame)
-    else:  # pragma: no cover
-        # Handle case where no original SIGINT handler was present.
-        return signal.default_int_handler(sig, frame)
-
-
-original_signal_handler = None
-
-
 class Client(base_client.BaseClient):
     """An Engine.IO client.
 
@@ -75,22 +56,6 @@ class Client(base_client.BaseClient):
                                     arguments passed to
                                     ``websocket.create_connection()``.
     """
-    event_names = ['connect', 'disconnect', 'message']
-
-    def __init__(self, logger=False, json=None, request_timeout=5,
-                 http_session=None, ssl_verify=True, handle_sigint=True,
-                 websocket_extra_options=None):
-        global original_signal_handler
-        if handle_sigint and original_signal_handler is None and \
-                threading.current_thread() == threading.main_thread():
-            original_signal_handler = signal.signal(signal.SIGINT,
-                                                    signal_handler)
-        super().__init__(logger=logger, json=json,
-                         request_timeout=request_timeout,
-                         http_session=http_session, ssl_verify=ssl_verify,
-                         handle_sigint=handle_sigint,
-                         websocket_extra_options=websocket_extra_options)
-
     def connect(self, url, headers=None, transports=None,
                 engineio_path='engine.io'):
         """Connect to an Engine.IO server.
diff --git a/tests/async/test_client.py b/tests/async/test_client.py
index 665a3a4..d71f664 100644
--- a/tests/async/test_client.py
+++ b/tests/async/test_client.py
@@ -1473,7 +1473,7 @@ def test_write_loop_websocket_bad_connection(self):
         _run(c._write_loop())
         assert c.state == 'connected'
 
-    @mock.patch('engineio.client.original_signal_handler')
+    @mock.patch('engineio.base_client.original_signal_handler')
     def test_signal_handler(self, original_handler):
         clients = [mock.MagicMock(), mock.MagicMock()]
         base_client.connected_clients = clients[:]
diff --git a/tests/common/test_client.py b/tests/common/test_client.py
index dacc4b4..4f45932 100644
--- a/tests/common/test_client.py
+++ b/tests/common/test_client.py
@@ -1715,12 +1715,12 @@ def test_write_loop_websocket_bad_connection(self):
         c._write_loop()
         assert c.state == 'connected'
 
-    @mock.patch('engineio.client.original_signal_handler')
+    @mock.patch('engineio.base_client.original_signal_handler')
     def test_signal_handler(self, original_handler):
         clients = [mock.MagicMock(), mock.MagicMock()]
         base_client.connected_clients = clients[:]
         base_client.connected_clients[0].is_asyncio_based.return_value = False
         base_client.connected_clients[1].is_asyncio_based.return_value = True
-        client.signal_handler('sig', 'frame')
+        base_client.signal_handler('sig', 'frame')
         clients[0].disconnect.assert_called_once_with()
         clients[1].disconnect.assert_not_called()