--- 3m-810.pl	2009/06/01 18:36:42	38
+++ 3m-810.pl	2009/06/01 21:07:11	39
@@ -398,7 +398,6 @@
 sub writechunk
 {
 	my $str=shift;
-warn "DEBUG: ", as_hex($str);
 	my $count = $port->write($str);
 	my $len = length($str);
 	die "wrong write length $count != $len in ",as_hex( $str ) if $count != $len;
@@ -440,6 +439,8 @@
 sub assert {
 	my ( $from, $to ) = @_;
 
+	return unless $assert->{expect};
+
 	$from ||= 0;
 	$to = length( $assert->{expect} ) if ! defined $to;
 
@@ -517,7 +518,7 @@
 	} sort { length($a) <=> length($b) } keys %$dispatch;
 	warn "?? payload dispatch to ",dump( $payload, $dispatch, $to ) if $debug;
 
-	if ( defined $to ) {
+	if ( defined $to && $payload ) {
 		my $rest = substr( $payload, length($to) );
 		warn "## DISPATCH payload to with rest", dump( $payload, $to, $rest ) if $debug;
 		$dispatch->{ $to }->( $rest );