can somebody show me a MDB2 dsn with port number?

hello pgsql-php,

i looked for a sample of MDB2 dsn array with port number, couldn't find
one.
my dsn without it is:
$dsn_postgresql=array(
'phptype' => "pgsql",
'username' => $pg_username,
'password' => $pg_password,
'hostspec' => "localhost",
'database' => $pg_database
);
$options = array(
'debug' => 9,
'portability' => DB_PORTABILITY_ALL,
);

the MDB2 docs have just

Most variations are allowed:

1 phptype://username:password(at)protocol+hostspec:110//usr/db_file.db?mode=0644
2 phptype://username:password(at)hostspec/database_name
3 phptype://username:password(at)hostspec
4 phptype://username(at)hostspec
5 phptype://hostspec/database
6 phptype://hostspec
7 phptype(dbsyntax)
8 phptype

* I don't see PORTNUMBER in there anywhere*

"Additional keys can be added by appending a URI query string to the end
of the DSN."
what does that mean?

and my connect call is

global $dsn_mysql,$dsn_postgresql,$DEBUG_DICT_CONNECT,$options;
// default has always been mysql, if (!$dsn) $dsn = $dsn_mysql;
// if (!$dsn) $dsn = $dsn_postgresql;
if (!$dsn) $dsn = $dsn_mysql;
// Retries connection to server 5 times.
if ($DEBUG_DICT_CONNECT) echo "dsn = " . print_r($dsn) . "<br>";
if ($DEBUG_DICT_CONNECT) echo "dsn = " . print_r($dsn) . "<br>";
$db = MDB2::connect($dsn,$options);

I have tried
$pg_options = array(
'portnumber' => 5534,
'debug' => 9,
'portability' => DB_PORTABILITY_ALL,
);

but connection fails.

can somebody cut and paste me one please?
thanks everybody.
joseph.