Serial Port Connector - 25-pin

                         1 1 1 1
                         3 2 1 0 9 8 7 6 5 4 3 2 1
                     ┌───────────────────────────────┐
                      \  ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■  /
                        \ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ /
                         └───────────────────────┘
                          2 2 2 2 2 2 1 1 1 1 1 1
                          5 4 3 2 1 0 9 8 7 6 5 4

          Pin In/Out Signal Name         Pin In/Out Signal Name
          ─── ────── ─────────────       ─── ────── ─────────────
           1    na   not connected       14   na   not connected
           2    O    Transmit Data       15   na   not connected
           3    I    Receive Data        16   na   not connected
           4    O    Request to Send     17   na   not connected
           5    I    Clear to Send       18   na   not connected
           6    I    Data Set Ready      19   na   not connected
           7    na   Signal Ground       20    O   Data Terminal Ready
           8    I    Data Carrier Detect 21   na   not connected
           9    na   not connected       22    I   Ring Indicate
          10    na   not connected       23   na   not connected
          11    na   not connected       24   na   not connected
          12    na   not connected       25   na   not connected
          13    na   not connected

   Notes: ■ The signals on pins 5, 6, 8, and 22 are represented at port
            n+6 (where n is the base port; e.g., at port 3feH on COM1).
            See Serial Ports.

          ■ A serial port cable for normal data transfer with the DOS
            InterLink utility uses only three wires.  For remote copy
            operations, you need a 7-wire null-modem cable.  See
            InterLink Cables.

See Also: Cables and Pin Outs
          Serial Port Connector - 9-pin
          Serial Ports
                                    -♦-