diff --git a/src/msw/dialup.cpp b/src/msw/dialup.cpp
index be2ba02e39..6cc5040544 100644
--- a/src/msw/dialup.cpp
+++ b/src/msw/dialup.cpp
@@ -830,7 +830,6 @@ bool wxDialUpManagerMSW::Dial(const wxString& nameOfISP,
     // default values for other fields
     rasDialParams.szPhoneNumber[0] = '\0';
     rasDialParams.szCallbackNumber[0] = '\0';
-    rasDialParams.szCallbackNumber[0] = '\0';
 
     rasDialParams.szDomain[0] = '*';
     rasDialParams.szDomain[1] = '\0';