Int 62 Fn 0C  - Cswitch - Read Message                                     [T]

   AH = 0Ch
   CX = number of bytes to read
   DS:SI -> buffer
   DX = queue number (0-63)

Return: AX = FFFFh bad queue number
        else  number of bytes transferred

See Also: AH=0Ah,AH=0Bh