diff --git a/fhem/FHEM/00_ZWDongle.pm b/fhem/FHEM/00_ZWDongle.pm
index f38e4bd49..c83b5b5c8 100755
--- a/fhem/FHEM/00_ZWDongle.pm
+++ b/fhem/FHEM/00_ZWDongle.pm
@@ -394,7 +394,7 @@ ZWDongle_Write($$$@)
   my ($hash,$fn,$msg,$noStack) = @_;
 
   if(!$noStack && $msg =~ m/^13/) { # SEND_DATA, wait for ACK
-    InternalTimer(gettimeofday()+0.5, "ZWave_HandleSendStack", $hash, 0)
+    InternalTimer(gettimeofday()+1, "ZWave_HandleSendStack", $hash, 0)
       if(!int(@{$hash->{SendStack}}));
     push @{$hash->{SendStack}}, $msg;
     return if(int(@{$hash->{SendStack}}) > 1);
@@ -413,7 +413,7 @@ ZWave_HandleSendStack($)
   RemoveInternalTimer($hash);   # remove timer to avoid re-trigger
   return if(!@{$hash->{SendStack}});
   ZWDongle_Write($hash, "00", $hash->{SendStack}->[0], 1);
-  InternalTimer(gettimeofday()+0.5, "ZWave_HandleSendStack", $hash, 0);
+  InternalTimer(gettimeofday()+1, "ZWave_HandleSendStack", $hash, 0);
 }
 
 #####################################