LCUS-8 USB Relay Module 8 Channel

[arthur64]

I'm working on a new project to control my hottub.  I'm designing using a RasPi 3+ and an 8 chan relay board.  I have a php function that does "$fd = fopen (/dev/ttyUSB0, w+) and fprint (fd, "0x%s", an octal string);  and relay 1 turns on, turns off - as does 2 thru 8. on off on off on... life is good.  

My problem:  Mfg info says 0xFF will return the status of all 8 relays as in "00100110".  I have tried all sorts of combinations of fprint 0xFF which seems to go OK.  Then fgets, fscanf, fread and the code just hangs.   Has anyone gotten this to work?  Can someone offer some help?

Thanks in advance.  (I'll owe u a beer)