Read Socket in PHP, receive only Trash - php

Question

i try to read gps data from my Teltonika router. I can receive data, but that are only trash for my eyes. So i cant parse that.
That are my received data: (the red is my IMEI Number...)
And that is my PHP:
<?php
require_once 'FMXXXX_Parser/Parser.class.php';
if(!($sock = socket_create(AF_INET, SOCK_DGRAM, 0))) {
$errorcode = socket_last_error();
$errormsg = socket_strerror($errorcode);
die("Couldn't create socket: [$errorcode] $errormsg \n"); }
echo "Socket created \n";
if( !socket_bind($sock, '10.81.0.1' , 62250) ) {
$errorcode = socket_last_error();
$errormsg = socket_strerror($errorcode);
die("Could not bind socket : [$errorcode] $errormsg \n"); }
echo "Socket bind OK \n";
$remote_ip = '10.81.0.1';
$remote_port = 62250;
while(1) {
echo "Waiting for data ... \n";
$r = socket_recvfrom($sock, $buf, 4096, 0, $remote_ip, $remote_port);
echo "$remote_ip : $remote_port -- " . $buf;
die;
}
socket_close($sock);
Have somebody an idea?