S I M P L E   M O D E M

     for BAUDAUT, AMTOR, PACTOR, SSTV, FAX, HF/VHF PACKET

                          BY RT4UZ


                                  Computer RS-232
                    COM1                                  COM2
                25-Pin  9-Pin                         25-Pin  9-Pin
                 20     4   DTR   -------------- DCD  8     1

                  5     8   CTS   -+
                                    ¦
                  8     1   DCD   ---------+
                                            ¦
                  4     7   RTS   ---------+---- RI  22     9
                                            ¦ ¦
                                            ¦ ¦
  Transceiver                               ¦ ¦
                                            ¦ ¦
        100 nF       µA741 (or similar)     ¦ ¦
                           +-----------¦+----+-- DTR 20     4
         ¦¦           3 ¦\ ¦7   ¦   ¦      ¦  ¦
   -----¦+-------------¦+\¦    ¦ +-+--¦+-+  ¦
         ¦¦   ¦         ¦  \ 6  ¦ ¦ ¦         ¦
   AF IN      ¦         ¦   >---+-+-+---------+-- DSR  6     6
              ¦       2 ¦  /    ¦ ¦ ¦         ¦
   ---+      ¦    +----¦-/¦    ¦ ¦ +--¦+--+ ¦
       ¦      ¦    ¦    ¦/ ¦4   ¦ ¦         ¦ ¦
       ¦     +-+  +-+      +----+------¦+----+-- RTS  4     7
       ¦ 100k¦ ¦  ¦ ¦100k  --- ---+        ¦  ¦
       ¦     +-+  +-+     +--- ---         ¦  ¦
       ¦      ¦    ¦    1µF ¦   ¦ 1µF   +--+--+-- GND  7     5
      ---    ---  ---   16V--- ---16V  --- ¦  ¦
     PTT -----------+                     ¦+-+
                     ¦                     ¦¦
                      \¦    +----+     SW1 ¦¦"HAMCOM"
                       +----¦    +--¦+-+ ++¦
                      /¦    +----+       \  ¦
                     +        3k          +-+"BAYCOM"
                    ---
                          +----+   +----+
        100nF    +--------¦91 k+---¦10 k+-------- TXD  2     3
          ¦¦ 10k+-+     ¦ +----+ ¦ +----+
   MIC --¦+----+-+-   ¦        ¦
          ¦¦    +-+   -----    -----
                 ¦    -----    -----
       ----+    ¦     1¦nF    30¦nF
           ---  ---    ---      ---



    SW1 used to switch between STANDARD HAMCOM mode
   for MIX v2.5, JVFAX v5.1, HAMCOM v2.1, TV2 v1.0 etc and
   EMULATE BAYCOM mode for BAYCOM v1.50, PCTOR v2.06.

   ..........................................................

   EMULATE BAYCOM mode requires additional small program EMBAYCOM.EXE
   and two COM-ports. 

     www.qsl.net/eb7dtm