DRA-50M Header / Jumper Settings
NOTE - REV2 comments in brackets [ ]


Header - Jumper Summary:

JU1 - Not present on the DRA-50M
JU2 - Not present on the DRA-50M
JU3 - Remove this short "shunt" to disable AllStar Link COS. (Remove for Digital Use)
JU4 - Not present on the DRA-50M
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) 
PTT - One of two jumpers to select transistor or relay PTT keying. [REV2 Only - see note below]
PTT - Two of two jumpers to select transistor or relay PTT keying. [REV2 Only - 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 JU6 - but not required.  In the transistor position - select the position of JU6 
as required and detailed below.


By default, we recommend NOT installing the short on JU3 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:


Jumper JU3  - AllStar Link COS logic input:
The hardware COS input (used for AllStar Link) is not needed for VARA FM or other digital 
modes. This function is disabled by removing "JU3". As such, even if this pin (6) is connected 
to the radio, it won't matter - their existence won't affect the operation of the DRA-50M for 
digital use.  If something is connected to the COS input (Windows Volume DOWN) bad things can 
happen with digital programs - like an unwanted change (reduction) in TX audio level.

JU3 is installed to enable the AllStar Link or Echolink functionality.  
Default is it's 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 a radio is connected 
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 - unless using the relay option with REV2 boards.

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 and JU6 for 
VARA or other digital mode usage.