DRA-30M REV2 Header and Jumper Assignments:


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 - Install this jumper to enable the Left Audio Output. 
JU4 - Install this jumper to disable PTT LED falsing protection.
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.


By default, we recommend NOT installing (or side-stepping) the jumpers on JU1 thru JU4 for VARA FM 
or other digital mode usage.  

Detailed explanation of these headers and jumpers:

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-30 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 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 Channel TX Audio Output:
JU3 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.

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.  Place this jumper if using the relay 
option to key the radio.

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 JU4 disables the BAT43 diode protection. Place this jumper if 
using the relay option to key the radio.

By default, we recommend NOT installing the jumpers on JU1 thru JU4 for VARA FM 
or other digital mode usage.