code   pin 
B1     40
B2     39
B3     38
B4     37
B5     36
B6     35
B7     34
B8     33
B9     32
B10    31
B11    30
B12    29
B13    28
B14    27
B15    26
B16    25
B17    24
B18    23
B19    22
B20    21
A1     20
A2     19
A3     18
A4     17
A5     16
A6     15
A7     14
A8     13
A9     12
A10    11
A11    10
A12    9
A13    8
A14    7
A15    6
A16    5
A17    4
A18    3
A19    2
A20    1

HITS:

         16   15   14    13     12     11    10    9      8      7      6       5     
         A5   A6   A7    A8     A9     A10   A11   A12    A13    A14    A15     A16      
38  B3   Fn  
37  B4        Esc  ½     Tab    Q      A     1     Z             
36  B5        <    F1    Caps   W      S     2     X        
35  B6        F4   F2    F3     E      D     3     C                           
34  B7        G    5     T      R      F     4     V      B           
33  B8             LCtrl                           RCtrl
32  B9        H    6     Y      U      J     7     M      N                         
31  B10       F6   ´     ¨      I      K     8     ,                                        
30  B11       no   F8    F7     O      L     9     .                          
29  B12       Ø    +     Å      P      Æ     0     '      -            
28  B13       F5   F9    Erase               F10   enter  space
27  B14                  LShift                    RShift        
26  B15                                                          leftm  rightm  midm
25  B16            del                       F11          down 
24  B17       Alt               ScrLk        PrtSc        AltGr
23  B18            ins                       F12          right       
22  B19            home                      end   pause  left     
21  B20            PgUp                      PgDn



To simplify matrix, connections done:
   15 - 7
   13 - 6
   11 - 5
   16 - 8
   38 - 26   

result:
                 col1 col2  col3   col4   col5  col6  col7   col8 
                 15   14    13     12     11    10    9      8      
                 A6   A7    A8     A9     A10   A11   A12    A13     
                 ---  ---   ---    ---    ---   ---   ---    --- 
row1  37  B4     Esc  ½     Tab    Q      A     1     Z             
row2  36  B5     <    F1    Caps   W      S     2     X        
row3  35  B6     F4   F2    F3     E      D     3     C                           
row4  34  B7     G    5     T      R      F     4     V      B           
row5  33  B8          LCtrl                           RCtrl        
row6  32  B9     H    6     Y      U      J     7     M      N                         
row7  31  B10    F6   ´     ¨      I      K     8     ,                                        
row8  30  B11    no   F8    F7     O      L     9     .                          
row9  29  B12    Ø    +     Å      P      Æ     0     '      -            
row10 28  B13    F5   F9    Erase               F10   enter  space
row11 27  B14               LShift                    RShift        
row12 25  B16         del                       F11          down 
row13 24  B17    Alt               ScrLk        PrtSc        AltGr
row14 23  B18         ins                       F12          right       
row15 22  B19         home                      end   pause  left     
row16 21  B20         PgUp                      PgDn               
row17 26  B15    leftm      rightm        midm              
row18                                                        fn
                                               
       
The keyboard matrix, as it is used in the code:

/* Not yet implemented... */
#define KEY_MIDM   KEY_App
#define KEY_RIGHTM MOD_RGUI
#define KEY_LEFTM  MOD_LGUI
#define KEY_FN     0


/* The keymap for a Thinkpad 600X keyboard */
const unsigned char keymap[NUMROWS][8] PROGMEM = { 
{0        ,KEY_Z      ,KEY_1     ,KEY_A    ,KEY_Q     ,KEY_tab   ,KEY_grave,KEY_esc  },
{0        ,KEY_X      ,KEY_2     ,KEY_S    ,KEY_W     ,KEY_cpslck,KEY_F1   ,KEY_Euro2},
{0        ,KEY_C      ,KEY_3     ,KEY_D    ,KEY_E     ,KEY_F3    ,KEY_F2   ,KEY_F4   },
{KEY_B    ,KEY_V      ,KEY_4     ,KEY_F    ,KEY_R     ,KEY_T     ,KEY_5    ,KEY_G    },
{0        ,MOD_RCTRL  ,0         ,0        ,0         ,0         ,MOD_LCTRL,0        },
{KEY_N    ,KEY_M      ,KEY_7     ,KEY_J    ,KEY_U     ,KEY_Y     ,KEY_6    ,KEY_H    },
{0        ,KEY_comma  ,KEY_8     ,KEY_K    ,KEY_I     ,KEY_rbr   ,KEY_equal,KEY_F6   },
{0        ,KEY_dot    ,KEY_9     ,KEY_L    ,KEY_O     ,KEY_F7    ,KEY_F8   ,0        },
{KEY_slash,KEY_bckslsh,KEY_0     ,KEY_smcol,KEY_P     ,KEY_lbr   ,KEY_minus,KEY_ping },
{KEY_spc  ,KEY_enter  ,KEY_F10   ,0        ,0         ,KEY_bckspc,KEY_F9   ,KEY_F5   },
{0        ,MOD_RSHIFT ,0         ,0        ,0         ,MOD_LSHIFT,0        ,0        },
{KEY_darr ,0          ,KEY_F11   ,0        ,0         ,0         ,KEY_del  ,0        },
{MOD_RALT ,0          ,KEY_PrtScr,0        ,KEY_scrlck,0         ,0        ,MOD_LALT },
{KEY_rarr ,0          ,KEY_F12   ,0        ,0         ,0         ,KEY_ins  ,0        },
{KEY_larr ,KEY_break  ,KEY_end   ,0        ,0         ,0         ,KEY_home ,KEY_uarr },
{0        ,0          ,KEY_pgdn  ,0        ,0         ,0         ,KEY_pgup ,0        },
{KEY_FN   ,0          ,0         ,0        ,0         ,0         ,0        ,0        },
{0        ,0          ,0         ,KEY_MIDM ,0         ,KEY_RIGHTM,0        ,KEY_LEFTM}};