Interrupt 11h	Equipment Check
(0:0044h)       fetch a code describing active peripherals. 
entry   AH      11h 
return  AX      Equipment listing word          Bits are: 
		0       number of floppy drives 
			0       no drives 
			1       bootable (IPL) diskette drive installed 
		1       math chip 
			0       no math coprocessor (80x87) present 
			1       math coprocessor (80x87) present 
	 (PS/2) 2       0       mouse not installed 
			1       mouse installed 
	  (PC)  2,3     system board RAM 
			0,0     16k    (PC-0, PC-1) 
			1,1     64k    (PC-2, XT) 
			note 1) not commonly used. Set both bits to 1 
			     2) both bits always 1 in AT 
		4,5     initial video mode 
			0,0     no video installed (use with dumb terminal) 
			0,1     40x25 color      (CGA) 
			1,0     80x25 color      (CGA, EGA, PGA, MCGA, VGA) 
			1,1     80x25 monochrome (MDA or Hercules, most super- 
			                          hires mono systems) 
Interrupt 11h  Equipment Check
(0:0044h)       fetch a code describing active peripherals. 
entry   AH      11h 
return  AX      Equipment listing word          Bits are: 
		6,7     number of diskette drives (only if bit 0  1) 
			0,0     1 drives 
			0,1     2 drives 
			1,0     3 drives 
			1,1     4 drives 
		8       0       DMA present  
			1       no DMA (PCjr, some Tandy 1000s, 1400LT) 
		9,A,B	number of RS232 serial ports (0-3)
			0,0,0   none 
			0,0,1   1 
			0,1,0   2 
			0,1,1   3 
			1,0,0   4 
		C       0       no game I/O attached 
			1       game I/O attached (default for PCjr) 
		D       serial accessory installation 
			0       no serial accessories installed 
			1       Convertible - internal modem installed 
			1       PCjr - serial printer attached 
Interrupt 11h  Equipment Check
(0:0044h)       fetch a code describing active peripherals. 
entry   AH      11h 
return  AX      Equipment listing word          Bits are: 
		E,F     number of parallel printers 
			0,0     none 
			0,1     one   (LPT1, PRN) 
			1,0     two   (LPT2) 
			1,1     three (LPT3) 
			note    Models before PS/2 would allow a fourth 
			        parallel printer. Remapping of the BIOS in the 
			        PS/2s does not allow the use of LPT4. 


See also:

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