The byte order for 8052 processors depends on the used compiler. Keil use Big endian while SDCC use Little endian p.e.
All intel based PC with x86 processors I know use little endian byte order.
If you develop do byte order switching on the PC driver side. Discribe that your device use a specific byte order nevertheless to witch host is is connected.
Also the tcp/ip protokoll always use big endian.

A sample how to detect and convert

/* swap bytes to little-endian if host cpu isn't it */
static unsigned short _swap16(unsigned short var)
{
union test {
unsigned short r;
unsigned char b[2];
} t;
unsigned char c1;/* swap bytes to little-endian if host cpu isn't it */
static unsigned short _swap16(unsigned short var)
{
union test {
unsigned short r;
unsigned char b[2];
} t;
unsigned char c1;
t.r=0x55AA;
if (t.b[0]==0xAA) /* little endian machine */
return var;
t.r = var;
c1=t.b[0];
t.b[0]=t.b[1];
t.b[1] = c1;
return t.r;
}

BTW a similar algorthmus is included in all UNIX systems with will run on 32-bit processors with different byte orders to make the code machine independent.