'incoming-fwd' => sub {
        my $id = shift;

        #
        #       FWD numbers could (in theory) start with '393' or '1393',
        #       followed by zero or more '9's, so strip this prefix if present
        #
        $id =~ s/^1?3939*//;

        return std_handler($id) if length($id) >= 10;
        return "$prefixes{fwd}$id";
    },