php tcp socket listener data parse - php

Question

I have gps tracker which is sending data to my server over tcp and my server has been coded in PHP. the device is sending data in every 5 seconds. The issue is that the first response comes fine as soon as socket established connection with the client but then subsequent responses comes in weird characters and no idea of how to interpret them.
Server.php code
SocketServer.class.php
<?php
require_once("SocketServer.class.php");
$server = new SocketServer("172.xx.xx.xxx",8000);
$server->max_clients = 10;
$server->hook("CONNECT","handle_connect"); // Run handle_connect every time someone connects
$server->hook("INPUT","handle_input");
$server->infinite_loop();
function handle_connect(&$server,&$client,$input) {
SocketServer::socket_write_smart($client->socket,"String? ","");
}
function handle_input(&$server,&$client,$input) {
$trim = trim($input);
if(strtolower($trim) == "quit")
{
SocketServer::socket_write_smart($client->socket,"Oh... Goodbye...");
$server->disconnect($client->server_clients_index); // Disconnect this client.
return;
}
$output = strrev($trim);
SocketServer::socket_write_smart($client->socket,$output);
SocketServer::socket_write_smart($client->socket,"String? ","");
}
Output:
Triggering Hook 'handle_connect' for 'CONNECT'
*HQ,9176952312,V6,115939,V,3127.2665,N,07307.6974,E,0.00,126.00,100822,FFF7FBFF,410,1,325,14688,8992300001243970980F,#
Triggering Hook 'handle_input' for 'INPUT'
0#119.160.59.240 --> $?v?#uY"1'&e0v?
&????ʧ?E9`,
Triggering Hook 'handle_input' for 'INPUT'
0#119.160.59.240 --> $?v?#uY"1'&e0v?
&????ʧ?E9`,
hex dump if data comes correctly
<Buffer 2a 48 51 2c 39 31 37 36 39 35 32 33 37 35 2c 56 36 2c 31 35 35 37 32 32 2c 56 2c 33 31 32 37 2e 33 30 33 34 2c 4e 2c 37 33 30 37 2e 36 36 33 36 2c 45 ... 65 more bytes>
Hex dump incorrect response
24 91 76 95 23 75 15 57 24 10 08 22 31 27 30 34 04 07 30 76 63 0c 00 00 00 ff f7 fb ff 00 01 c7 f0 00 00 00 00 01 9a 01 01 45 7f 2d 00