http://nemesis.lonestar.org/reference/telecom/modems/dtedce.html
Din 8            Modem   DTE   Cisco RJ45
1       RTS      4/20          1 青
2       DCD/DSR  6             7 茶
3       TD       2             3 黒
4       GND      7             4 赤
5       RD       3             6 黄
6     
7       CTS      8
8       
at http://margo.student.utwente.nl/el/componen/fpinout3.html

7.17) Mini DIN-8 Macintosh Serial Connector

(From Daniel JB Clark)

        /------@@@------\         1 HSKo      Output Handshake
      /        @@@        \                   (Zilog 8530 DTR pin)
    /                       \     2 HSKi/CLK  Input Handshake OR
   /     [|]   [|]   [|]     \                External Clock
  /       8     7     6       \   3 TxD-      Transmit data (-)
 |                             |
 |                             |  4 Ground    Signal ground
 |     ===       ===    ===    |
 |      5         4      3     |  5 RxD-      Receive data (-)
 |                             |
 |                             |  6 TxD+      Transmit data (+)
  \----+    ===   ===    +----/
   \@@@|     2     1     |@@@/    7 N/C       (no connection)
    \@@|                 |@@/
      \|                 |/       8 RxD+      Receive data (+)
        \------@@@------/
               @@@
Above drawing is bottom view of the box side of the connector.
(Say, looking at the connector of the computer from outside)
Some related info in Japanese -> http://www.ki.nu/~makoto/diary/2007/08/15/