DRA-36 Header & Jumper Settings

Header - Jumper Summary:

JU1 - Install this jumper to enable AllStar Link COS - Remove for Digital. 
JU2 - Install this jumper to enable AllStar Link CTCSS - Remove for Digital.
JU3 - Selects between the "L" Left Audio Output or  "R" Right Audio Output.
JU4 - Install this jumper to disable PTT LED falsing protection.
JU5 - Selects between "A" 1200 and "B" 9600 receive baud audio type.
PTT Headers - selects the type of transmitter keying method (Transistor or Relay).

R12 (the larger blue pot) controls the receiver audio level.

By default, we recommend NOT installing the jumpers on JU1 and JU2 for VARA FM 
or other digital mode usage.  

Detailed explanation of these headers and jumpers:

PTT Headers and Jumpers:
2-pin headers are arranged in a square near the relay.  This allows two jumpers
to installed "side-by-side" covering all four pins. The arrangement can be 
parallel or perpendicular to the circuit board edge.  These 2-pin headers 
select the type of PTT keying method.  Transistor or Relay keying is possible.  
Two jumper (shorts) go side-by-side in one direction for transistor keying, or 
are removed and rotated 90 degrees for relay keying. A "R" and "T" along with 
some arrows on the silk screen indicate which way the jumpers need to be 
positioned to select either method.  BOTH jumpers are required for either 
push-to-talk method to work. 

JU1 and JU2 - AllStar Link COS and CTCSS logic inputs:
The hardware COS and CTCSS inputs (used for AllStar Link) are not needed for 
VARA FM or other digital modes. In fact, if something is connected to the COS 
and CTCSS (Windows Volume UP and DOWN pins) bad things can happen with digital 
programs. In addition, DCD (XDC) and/or other logic or control lines might be 
connected in existing installations using the KPC-3 or similar TNC. These functions
affect pins 2 and 4 on the DB9. These DB9 pins can be disabled by the absence of 
the "JU" jumpers at locations JU1 and JU2. As such, even if these pins are tied 
back to the radio somehow, it won't matter - their existence won't affect the 
operation of the DRA-36 for digital use. Jumpers can be installed into locations 
JU1 and JU2 to restore the AllStar Link functionality.

Plus, these hardware inputs may be implemented sometime in future software - permitting 
DCD or some other digital feature, so I didn't want to limit the hardware from 
being able to use them in the future. 


JU3 - LEFT or RIGHT Channel TX Audio Output Selection
Left and Right channel audio is available on the DRA-36.  You can select which 
one feeds the transmitter by the position of JU3.  L is for Left and R is Right.
R14 adjusts the Right channel TX audio and R16 adjusts the Left.

JU4 - False PTT LED illumination protection:
Jumper JU4 is removed to enable this illumination protection.  The jumper can be 
placed if this option should it create a problem for a particular installation. 
The jumper simply shorts out the diode.

Why is JU4 necessary?
Partial (or full) illumination of the PTT LED can happen if the radio adapter is
connected to a radio that has a PTT switching voltage (bias) of less than 5 volts.
This is the case with many portable radios.  This situation causes the red PTT LED 
to partially illuminate. This illumination can also happen with just about any radio 
when the radio's power is turned off, falsely making it look like the radio is 
transmitting. Placing JU4 disables the BAT43 diode protection.

JU5 - Receive Audio Baud Rate Selection
Selects between "A" 1200 and "B" 9600 baud on radios that supply both types of audio.
Default is "B" 9600.

By default, we recommend NOT installing the jumpers on JU1, JU2, and JU4.
Additionally - by default JU3 is set to "R" and JU5 is set to "B" 9600 for fastest 
throughput.