diff --git a/fhem/FHEM/37_harmony.pm b/fhem/FHEM/37_harmony.pm
index e06a07595..97d4592f9 100644
--- a/fhem/FHEM/37_harmony.pm
+++ b/fhem/FHEM/37_harmony.pm
@@ -1172,6 +1172,8 @@ harmony_send($$)
   my ($hash, $data) = @_;
   my $name = $hash->{NAME};
 
+  return undef if( !$hash->{CD} );
+
   Log3 $name, 4, "$name: send: $data";
 
   syswrite $hash->{CD}, $data;