DRA-100-DIN6 Jumper Settings: Header - Jumper Summary - Details below this section. JU1 - Normally in the "L" position. JU2 - Normally removed - Install to enable AllStarLink CTCSS JU3 - Normally removed - Install to enable AllStarLink COS. JU4 - Normally in the "9600" position. JU5 - Normally in the "R" position. JU6 - Normally removed - Install to enable VOX. JU7 - Normally in the "Solid" position. "Flash" blinks the Power LED when COMM OK. JU8 - Normally installed. Remove to add attenuation to the RX path. JU9 - Normally installed. Remove to add attenuation to the TX path. 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 a detailed explanation of H1 and H2. Detailed explanation of these headers and jumpers: JU1 - VOX Input Selection - Controls which audio channel drives the VOX input. Position L = Left channel is sampled to drive the VOX. Position R = Right channel is sampled to drive the VOX. Default is "L". For detailed VOX operation, please see the article on the FAQ page. JU2 - CTCSS Enable / Disable - AllStar Link JU2 is placed to enable the CTCSS feature. JU2 is removed to disable the CTCSS feature. Default is removed. JU3 - COS Enable / Disable - AllStar Link JU3 is placed to enable the COS feature. JU3 is removed to disable the COS feature. Default is removed. JU4 - Receiver audio "type" selection. JU4 - 1200 Baud or 9600 Baud receiver audio selection (radio dependent). Default is 9600. HF operation sometimes requires 1200. JU5 - LEFT or RIGHT TX Audio Output to Pin 1 on the Mini-DIN-6 RADIO socket. JU5 selects between Left or Right transmit audio channels. L = Left - R = Right. Default is "R" because it retains the TX level pot on the front panel. Selecting "L" will work but requires R16 (small blue pot on the circuit board) to be adjusted for TX level and is otherwise inconvenient. JU6 - VOX Enable / Disable JU6 is placed to enable the VOX PTT feature. JU6 is removed to disable the VOX PTT feature. For detailed VOX operation, please see the DRA-100 VOX page. Default is removed. JU7 - Operation of the Power / Heart-Beat / COMM OK LED - Solid or Flash. JU7 changes the operation of the multi-color LED located on the left side of the front panel. This LED combines the status of Power, HB and COMM OK into one indicator light. On other DRA's, these are the Green and Blue LEDs. Upon powering the board - the Power LED illuminates Amber. When JU7 is set to "Solid" the Power LED will turn solid Green when HB is running and you'd expect to see the Blue LED solidly lit on any other DRA. When JU7 is set to "Flash" the Power LED alternately flashes between Yellow and Green when HB is running and you'd expect to see the Blue LED solidly lit on any other DRA. This action is not as "in your face"as a blinking Green LED. Those that already have others DRAs may want to see the flashing light, while others may prefer less distraction. Default is "Solid" JU8 - RX Audio level attenuator: JU8 is for the receive (RX) path. JU8 - Normally installed. Remove to add attenuation to the RX path. When a jumper are placed on this header, the audio level is not reduced. It is the same as other DRA. When removed, the receive level is reduced by 20 dB. JU9 - TX Audio level attenuator: JU9 is for the RIGHT channel transmit (TX) path (front panel TX control only). When a jumper are placed on this header, the audio level is not reduced. It is the same as other amplified DRAs. When removed, the transmit level is reduced by 20 dB. JU9 - Normally installed. Remove to add attenuation to the right channel TX path. NOTE: There is no selectable attenuation jumper for the left channel which is normally used for VOX operation. Only the internal blue pot R16 is used to physically adjust the level of the left channel. Normally R16 is set to mid rotation, or a little higher for proper VOX drive. By default, we recommend NOT installing the jumper shorting bar on JU2, JU3 and JU6 for VARA FM, VARA HF, SoundModem, fldigi, and DireWolf.