This machine has run near flawlessly for 10 years,
Yesterday it just stopped listening to the computer feeding the DNC (Serial over the tape Interface)

have tried 3 computers, 2 usb to serial adaptors and scratch made a new cable.
I have attached a logic analyzer and can confirm we are sending data.
The strange part is we can still pull data from Mazak to the PC.

Is there any silly thing we may have missed,
does anyone know if there is a method to try attach a FDD for a different load method? or does that come over the same interface anyway?

Also if there are any Service/Tech manuals people could point me toward would be much appreciated.