This is a little HOWTO attaching a terminal to an SGI Indigo2 (alternatively as PDF):

• Build yourself a suitable cable (costs about $4 and 30min of soldering)

mini DIN 8 (back) 
     __   __ 
    /  `-'  \ 
   | *  *  * |   8 7 6 
   | *   * * |  5   4 3 
   |  *   *  |   2   1 
    \_______/ 
  DSub 25 female (back)  
 _______________________________ 
 \                             / 
  \ * * * * * * * * * * * * * /     1  2  3  4  5  6  7  8  9 10 11 12 13 
   \ * * * * * * * * * * * * /       14 15 16 17 18 19 20 21 22 23 24 25 
    \_______________________/ 

cabeling scheme
 
  Dsub 25 female                    mini DIN 8 

     2 (TD)  ----------------------- 5 (RD) 
     3 (RD)  ----------------------- 3 (TD) 
     4 (RTS) ----------------------- 2 (CTS) 
     5 (CTS) ----------------------- 6 (RTS) 
     6 (DSR) --------+-------------- 1 (DTR) 
                     | 
     8 (CD)  --------+ 
    20 (DTR) ----------------------- 7 (CD) 
     7 (SG)  ----------------------- 8 (SG) 

• Test the cable
• Attach the cable to indigo and terminal
• Modify/Add /etc/inittab entry (this is one single line!)

vt:23:respawn:/sbin/suattr -C CAP_FOWNER,CAP_DEVICE_MGT,CAP_DAC_WRITE+ip -c

   "exec /sbin/getty ttyf1 dx_9600 vt100" 

• Restart init (as root)

# init q

• Switch on terminal
• Configure terminal (press F3, sometimes F2 and/not holding SHIFT down)
• Set terminal to 9600,8,N,1
• Save terminal configuration
• Have fun