DRA-36M Header & Jumper Settings

Header - Jumper Summary:

JU1 - Install this jumper to enable AllStar Link COS - Remove for Digital. 
JU2 - Not installed on DRA-36M
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 - One of two jumpers to select transistor or relay PTT keying. See note below.
PTT - Two of two jumpers to select transistor or relay PTT keying. See note below.

NOTE:
The PTT keying method is selectable by two mechanical jumpers. You choose between Transistor or
Relay keying.  The selection between transistor and relay keying is done with a pair of 
two - 2-pin headers in a square arrangement.  These headers are red and require two jumpers 
to be placed in either a up/down or back/forth (vertical or horizontal) side-by-side orientation.
Both jumpers are required for the option to work correctly.  The up/down position selects the 
relay, while the back/forth position selects the transistor.  These headers are located in a 
square box labeled "PTT" near the relay.  If the relay position is selected - it's best to 
also place JU4 - but not required.  In the transistor position - select the position of JU4 
as required and detailed below.


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

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

Detailed explanation of these headers and jumpers:

PTT Headers and Jumpers:
Two 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 - AllStar Link COS logic input:
The hardware COS input (used for AllStar Link) is not needed for VARA FM or 
other digital modes. In fact, if something is connected to the COS 
(Windows Volume DOWN pin) 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. This function affect pins 6 on the 
MINI-DIN-6. This pin can be disabled by the absence of the "JU1" jumper.
As such, even if this pin is tied back to the radio somehow, it won't matter - 
its existence won't affect the operation of the DRA-36M for digital use. A jumper
can be installed into location JU1 to restore the AllStar Link functionality.

Plus, this hardware input 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 it 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 and JU4.
Additionally - by default JU3 is set to "R" and JU5 is set to "B" 9600 for fastest 
throughput.