diff --git a/apprise/plugins/smpp.py b/apprise/plugins/smpp.py
index 21fa1bf4..4cc84829 100644
--- a/apprise/plugins/smpp.py
+++ b/apprise/plugins/smpp.py
@@ -116,6 +116,7 @@ class NotifySMPP(NotifyBase):
             'type': 'string',
             'regex': (r'^[0-9\s)(+-]+$', 'i'),
             'required': True,
+            'map_to': 'source',
         },
         'target_phone': {
             'name': _('Target Phone No'),