BULLETIN:  SB0250
VENDOR:    KENWOOD
SUBJECT:   WIRING OF TS440 ACC2

USING THE ACC 2 DATA JACK ON THE TS-440 FOR DIGITAL, RTTY.

    The TS-440  ACC 2 jack (13) pin can be used for your TNC hookup with
  great success. The advantages are :
    1. you can leave your microphone connected at all times
    2. you can turn your speaker volume up and down without affecting the
       RX level into your TNC.
    3. It keeps your whole setup simple and reduces it to one cable.
    4. Your Mic gain will now set at 7 or 8 on it's dial. YES!

   The pins used on ACC 2 are:  ( see page 11 of TS-440 manual)
   (3) Data output. This is a constant 300 mv output that will go to
       your TNC audio input lead. (Note) This audio level is also
       the audio output on the RCA jack used for FSK output .
       This is where many hook up their phone patch.

        The audio output may be too hot for some TNC units. if so you
       will have to pad down this level with resistors. My KAM wants
       to see 50 mv and it's seeing 300 mv. so far so good!

   (4) Microphone shield (Ground)

   (9) Microphone Mute. When pulled to ground, this pin will mute the
       front Mic connector ** AS LONG AS THE PROCESSOR SWITCH IS OFF!**
       If the switch is left on, the audio is pumped up too high to mute.
       Connect this pin to your PTT wire from your TNC and also connect
       the Cathode of a switching diode (1N4148, 1N914, etc). The Anode of
       the diode will go to pin (13). ( The cathode is the bar)

       When pin 9 is pulled low by your PTT wire, the diode will cause pin
       12 to go low enough to put the 440 into transmit. This will both mute
       the front Mic jack and transmit at the same time. Works great!
           If the diode is not used, and the pins are just connected
       together, the front Mic jack will mute it's self when used.
           NOT A GOOD IDEA!
   (11) This is your transmit audio in, from your TNC.
        Setting of MIC gain on front of radio:
        1. The audio level in wants to be 500mv RMS (1.5 vpp or so). For the
           KAM remove its jumper inside. This will give you max audio out of
           the TNC.
        2. For the PK-232, turn up the audio output pot until you get
           500mv or so RMS . You may also want to set it to make your 440
           Mic gain poy read where you want it.
            (MIC) will run around 7 or 8 for digital with the KAM. I'm not
            sure for the pk-232. more level into the 440, lower numbers on
            the audio pot (MIC)
   (12) Ground for audio shield

   (13) Standby (transmit). this connects to the Anode (no bar) of the diode
        from pin (9)
        When pin (9) is pulled low, pin(13) will go low .

                            To sum it all up:
        1. You will need:
                        1.  diode, 1N914, OR 1N4148
                        1.  13 PIN DIN CONNECTOR
                        1.  TNC cable with appropriate connectors

        2. Remember to keep the processor switch OFF!
        3. Set the Mic gain to 7 or 8 and look at the ALC, keep it in the
           red, as per the book. Lower power, longer transmit time!
     Good Luck, this hookup in being used with 3 TS-440 radios and is
       working great! Go slow and solder carefully. Please recheck your work
       and then plug it in!