http://www.vintage-computer.com/vcforum/showthread.php?11397-Possible-lead-on-an-AT-amp-T-PC-6300-WGS

DIPSW-0 Position 1-4
  0111  128k RAM on motherboard
  1011  256k
  0011  256k                    + 128k on expansion board
  1101  256k                    + 256k
  0101  256k                    + 384k
  1110  512k on motherboard BANK0
  0110  512k                      + 128k on motherboard BANK1
  0100  128k                      + 512k

DIPSW-0 Position 5
  1     8087 not installed
  0     8087 installed

DIPSW-0 Position 6
  0     Z8530 comm. controller installed
  1     8250 installed

DIPSW-0 Position 7
  not used

DIPSW-0 Position 8
  1     2732 EPROMs installed
  0     2764 EPROMs installed

DIPSW-1 Position 1
  0     96 TPI diskette drives (720k)
  1     48 TPI diskette drives (360k)

DIPSW-1 Position 2
  1     slow diskette startup (800 ms)
  0     fast diskette startup (250 ms)

DIPSW-1 Position 3-4
  11    use standard BIOS for harddisk control
  01    harddisk controller has its own BIOS

DIPSW-1 Position 5-6
  11    reserved
  00    monochrome display
  01    40x25 CGA display
  10    80x25 CGA display

DIPSW-1 Position 7-8
  11    1 diskette drive
  01    2 diskette drives
  10    3
  00    4