diff --git a/addons/hw_escpos/__openerp__.py b/addons/hw_escpos/__openerp__.py
index 830b78300ea..d220eaef72e 100644
--- a/addons/hw_escpos/__openerp__.py
+++ b/addons/hw_escpos/__openerp__.py
@@ -37,6 +37,9 @@ that would need such functionality.
 """,
     'author': 'OpenERP SA',
     'depends': ['hw_proxy'],
+    'external_dependencies': {
+        'python' : ['usb.core'],
+    },
     'test': [
     ],
     'installable': True,