How to create a null-terminated string in php?

Question

PHP

To communicate with the device I use sockets and php.
The following code works fine: we take a null-terminated string and send it to the socket

$msg = "\x00\x00\x00\x00\x63\x03\x67";
socket_write ( $socket , $msg, strlen($msg));

But when trying to dynamically create such a string like this:

$data = "00000000630367";
$msg = "\x".implode("\x",str_split($data,2))

I get an ordinary string, and, accordingly, when sent to the device, it does not understand what I want.
How to correctly generate a request?

Answer 1

hex2bin

Answer 2

\x00is a sequence substituted by PHP at file compilation time, not at runtime.
If you want to get a character by its numeric code, there is a function:
php.net/manual/en/function.chr.php