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Serial Port DB9-Male DB25-Male
9-pin   25-pin  assignment
1       8       DCD (Data Carrier Detect)
2       3       RX  (Receive Data)
3       2       TX  (Transmit Data)
4       20      DTR (Data Terminal Ready)
5       7       GND (Signal Ground)
6       6       DSR (Data Set Ready)
7       4       RTS (Request To Send)
8       5       CTS (Clear To Send)
9       22      RI  (Ring Indicator)


DB-9 Connector
    Pin   Signal                   Pin  Signal
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     1    CD   Carrier Detect       6   DSR  Data Set Ready
     2    RXD  Receive Data       * 7   RTS  Request to Send
     3    TXD  Transmit Data        8   CTS  Clear to Send
   * 4    DTR  Data Term. Ready     9   RI   Ring Indicator
   * 5    GND  Signal GND

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5pin DIN Male          DB15-S Male
    --+--               ----------------------
   /  ^  \              \   1  2  3  4  5    /
  | 1   3 |              \ 6  7  8  9 10    /
   \ 425 /                \ 11 12 13 14 15 /
    -----                  ----------------

DB9 Male                DB15 Male
-------------           --------------------------
\ 1 2 3 4 5 /           \ 1  2  3  4  5  6  7  8 /
 \ 6 7 8 9 /             \ 9  10 11 12 13 14 15 /
  ---------               ----------------------

DB25 Male                             IDC-50 Male
 ------------------------------        -------------------
 \ 1  2  3  4  5  7  8 ... 13 /       | 1  3  5  7 ... 49 |
  \ 12 13 14 15 16 .......25 /        | 2  4  6  8 ... 50 |
   --------------------------          -------------------

(Power Connector) Male
  __________
 /          \
| 4  3  2  1 |
 ------------
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