function createSocketSendHexMsgWaitReply($mac, $hexMsg, $s20Table)
{
//
// Sends msg specified by $hexMsg, in hexadecimal, to device
// sepcified by $mac and waits for reply.
//
// Returns the reply in hex format after checking major conditions
//
$ip = $s20Table[$mac]['ip'];
$s = createSocketAndBind($ip);
$hexRecMsg = sendHexMsgWaitReply($s, $hexMsg, $ip);
socket_close($s);
return $hexRecMsg;
}
function sendAction($mac, $action, $s20Table)
{
//
// Sends an $action (ON=1, OFF = 0) to S20 specified by $mac
// It retries until a proper reply is received with the desired
// power status
// However, we have detected that the reported power status just
// after an action fails sometimes, and therefore you should not
// use this function alone. Prefer switchAndCheck() below, which
// performs a double check of the final state.
//
subscribe($mac, $s20Table);
$msg = ACTION . $mac . TWENTIES;
if ($action) {
$msg .= ON;
} else {
$msg .= OFF;
}
$ip = $s20Table[$mac]['ip'];
$s = createSocketAndBind($ip);
$hexRecMsg = sendHexMsgWaitReply($s, $msg, $ip);
$status = (int) hexdec(substr($hexRecMsg, -2, 2));
socket_close($s);
}