DRA-45 Header - Jumper Assignments:

Header - Jumper Summary:

JU1 - Normally in the "B" position.
JU2 - Normally in the "A" position.
JU3 - Remove this short "shunt" to disable AllStar Link COS   (Remove for Digital)
JU4 - Remove this short "shunt" to disable AllStar Link CTCSS (Remove for Digital)
JU5 - Remove this short "shunt" to disable the Left Audio Output
JU6 - Remove this short "shunt" to enable PTT LED falsing protection.
H1  - Install short over the center two pins of this 4-pin header.
H2  - Install short over the center two pins of this 4-pin header.

H1 and H2 are white 4-pin headers directly beside the LM-386 amplifiers. By default, 
a jumper short or "shunt" is installed onto the center two pins of the header. See 
the "H1 and H2 header pin assignments" document for details.

By default, we recommend NOT installing the short on JU3 thru JU6
for VARA FM or other digital mode usage.  

Detailed explanation of these headers and jumpers:

Local Control or Alarm Trip is a logic option that can enable a secondary 
control method, or trip an alarm. This feature is capable of toggling a control
 method or tripping an alarm line on a co-located repeater controller or other
 remote alarm if the DRA-45 should fail. JU1 controls the polarity of this 
function, explained below.

Jumper JU1 - Control / Alarm logic polarity.
Position A = DB9 pin 7 Logic is high when COMM OK LED not lit.
Position A = DB9 pin 7 Logic is low when COMM OK LED lit.
Position B = DB9 pin 7 Logic is low when COMM OK LED not lit.
Position B = DB9 pin 7 Logic is high when COMM OK LED lit.
Default is position "B"


Jumper JU2 - Audio amplifier powering.
Position A = Amplifiers powered from USB 5VDC. Suitable for many radio applications
where  the maximum required P-P voltage doesn't exceed 5 volts. 
Position B = Amplifiers powered from external source 6 to 15 VDC. Some radios 
require more than 5 volts P-P of audio. Many radios have a source of 10 to 15 volts
readily available. The voltage source must be well filtered but regulation isn't 
necessary as long as enough current is available for the load. Driving speakers 
will require a power source capable of several hundred mA.,depending on speaker 
impedance and desired listening level.
Default is position "A"


Jumpers JU3 and JU4  - 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 JU3 and JU4  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-45 for digital use.  Jumpers can be installed into locations 
JU3 and JU4 to restore the AllStar Link functionality.
Default is both JU3, and JU4 is removed.

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


JU5 - LEFT Channel TX Audio Output:
JU5 is removed to prevent the Left Audio Channel from being connected to the 
DB9. In many cases, the Right Audio Channel is used for connecting to the radio 
and the Left Channel is not used. In existing installations, there may be 
instances where this pin (8) of the DB9 is connected to something, and disabling 
the pin by removing the jumper is desired.
Default is installed.  Remove for reuse of Kantronics cables.


JU6 False PTT LED illumination protection:
Jumper JU6 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 it 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 JU6 disables the BAT43 diode protection.
Default is JU6 is removed.


By default, we recommend NOT installing the shorting bar on JU3, JU4, and JU6 for 
VARA FM or other digital mode usage. Remember to remove JU5 for reuse of existing 
Kantronics radio cables.