Int E0  - Dr Multiuser DOS - "a_readblk" - Read String From Aux Device     [O]

   CL = ACh
   DS:DX -> character control block (CHCB) (see below)

Return: AX = number of characters read
Desc:  read characters from the default auxiliary (AUXn:) device into a buffer
     until the buffer is full or the device is no longer ready

Notes: if the device is initially not ready, blocks until at least one
     character has been read
   if another process owns AUX, this call blocks until the device becomes
     available

See Also: INT E0/CL=03h,INT E0/CL=A5h,INT E0/CL=ADh

Format of character control block (CHCB):
Offset Size    Description
 00h   DWORD   pointer to character buffer
 04h   WORD    length of character buffer