diff --git a/74_AMAD.pm b/74_AMAD.pm
index 351958c..46cc1ba 100644
--- a/74_AMAD.pm
+++ b/74_AMAD.pm
@@ -1127,7 +1127,7 @@ sub AMAD_CommBridge_Read($) {
     my $c;
     my $device = $header->{FHEMDEVICE} if(defined($header->{FHEMDEVICE}));
     my $fhemcmd = $header->{FHEMCMD} if(defined($header->{FHEMCMD}));
-    my $dhash = $defs{$device};
+    my $dhash = $defs{$device} if( $defs{$device} );