To: mbramwel
Date: Wed, 8 Nov 89 10:24:00 est

Subject: packet mod for TM321

From: rfc
Date: 5 Sep 89 14:37:21 GMT

Sender: news


 Msg# TSP  Size #Rd Date/Time MsgID        From   To

  2627 BF   1043   2 0904/0022 4650_WA2SNA  WM8J   ALL
   Sb:TM231PACKETMOD



    THE FOLLOWING IS AN EASY MOD TO SQUELCH THE AUDIO AT MIC PIN 6 FOR

    TNC'S



        WITHOUT TRUE DCD: OBTAIN FROM KENWOOD A 2SD1757(K) (SURFACE

MOUNT TRANSISTOR).  INSTALL EMITTER TO MIC PIN 8, COLLECTOR TO

MIC PIN 6, AND JUMPER FROM BASE TO THE UNUSED PIN ON CONNECTOR

202. USING THE UNUSED PIN RATHER THAN RUNNING THE JUMPER TO THE

        MOTHER BOARD PRESERVES THE PLUG IN FEATURE OF THE FRONT PANEL.

        CONNECT ONE END OF A 4.7 K RESISTOR (I USED A 6.8 K) TO THE

        MUTE LINE (IC 5 PIN 7), AND CONNECT THE OTHER END TO THE UNUSED

        PIN OF CONNECTOR 4, WHICH MATES WITH CONNECTOR 202.  THIS NEW

        CIRCUIT IS A CLOSE COPY OF THE AF MUTE CIRCUIT THAT SQUELCHES

        THE RX AUDIO AT THE SPEAKER. IT WORKS PERFECT WITH MY PACCOMM

        MICROPOWER 2.  THE HARDEST PART OF THE MOD IS REMOVING THE

        LOCKING RING AROUND THE MIC CONNECTOR. I USED A MODIFIED TABLE

        FORK! GOOD LUCK.



        0241z, 939 msgs, #2643 last


Note:I haven't tried this, proceed at your own risk! WA2ISE