DRA-50 Header / Jumper Settings


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 - Left or Right transmit audio source to DIN radio connector. (Default is A - Right)
JU6 - Remove this short "shunt" to enable PTT LED falsing protection. (Default is removed)
JU7 - A = 1200 Baud, B = 9600 Baud receiver audio selection. (Default is B - 9600) 
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, JU4 and JU6
for VARA FM or other digital mode usage. For wide-band operation, place JU7 in the "B" 
position, and JU5 in the "A" position and use R14 for transmit audio level.

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. These functions are disabled by removing the "JU" 
jumpers at locations JU3 and JU4  As such, even if these pins are connected to the 
radio, it won't matter - their existence won't affect the operation of the DRA-50 for 
digital use.  If something is connected to the COS and CTCSS inputs (Windows Volume UP
and DOWN pins) bad things can happen with digital programs - like an unwanted change 
in TX audio level.

JU3 and JU4 are installed to enable the AllStar Link functionality.  
Default is both are removed or side-stepped.

JU5 - LEFT or RIGHT TX Audio Output:
JU5 selects between Left or Right transmit audio channels. A = Right, B = Left.
Default is A - Right.

JU6 PTT LED false illumination protection:
Jumper JU6 is removed to enable this false 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 JU6 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 removed.

JU7 - Receiver audio baud rate selection. This header is right behind the DIN-6
radio connector.  It's in a tight location and later units have a jumper with a 
(blue) handle to make repositioning a little easier.
JU7 A = 1200 Baud, B = 9600 Baud receiver audio selection (radio dependent)
Default is B - 9600 Baud.

By default, we recommend NOT installing the shorting bar on JU3, JU4 and JU6 for 
VARA or other digital mode usage.