[RV7ator]

Questions for the brain trust:

1. Can the same 232 port receive from one device and transmit to another device, both having the same communication protocol?

2. Do I have a sick GDL39 (and/or 795)?

Two, first. The GDL39 manual (Para 4.2.1) says it should boot in Bluetooth pairing mode when powered remotely. It does not. Believing it would, I buried the GDL on the subpanel since once paired with a 795 it would re-connect each time avionics are powered up. Not so. It appears (Para 4.1.1 and 4.1.2) that the 795 must be powered and bluetoothing before powering the GDL and manually entering pairing mode by pressing the power button 5+ seconds. But, that's a non-starter since both are powered simultaneously from an avionics bus, and I can't reach the GDL without ducking under the panel. To top it all off, having initially paired the 795 and GDL, the 795 can't find the GDL anymore though it's a listed Bluetooth device. One or both seem to be sick. That notwithstanding, if I have to go through the rigmarole of re-pairing every time I want to fly...I won't have it.

As to hard wiring, it seems I'm out of 232 ports. Besides the GDL, there's a GTN650 and a Trio Pro Pilot involved. On the 795, Tx2 feeds the Trio, and Rx1 listens to the GTN (for a much larger map display). With both ports utilized and without Bluetooth, I can't get wx and traffic from the GDL into the 795.

IF, IF, Rx2 on the 795 can receive the GTN and still talk to the Trio on Tx2 (both seemly use the same "Aviation In/NMEA Out" configuration), that frees up the 795's Tx1/Rx1 to interface with the GDL's TxB/RxB.

So the question: can the same 232 port listen to and talk to two different devices?

To be really piggy about this, the GDL's TxA/RxA, so far unused, could be tied to the GDU's port 1.

I'm beginning to long for the good ol' days of testing a sack of vacuum tubes at the local drug store.

Answers greatly appreciated.

John Siebold

 

[Brantel]

John,

The manual says that when turned on by the remote switch input that the unit will go into pairing mode for 2 minutes. Just applying power does not. (Steve did hint on here that they plan to add this to the next firmware rev.)

You might try grounding the remote switch input all the time and see if this forces it to go into pairing mode when you put power to it. Not sure if this will work or not.

You should not have to re-pair the devices after a reboot.

Aviation In/NMEA out is made for being able to receive Aviation format from a Garmin panel mounted box like the GTN series and simultaneously sending NMEA data out to something like the TRIO AP. Should work fine.

Keep in mind that the GDL39 will only connect to port #1 on the 795. The GDL39 needs 2 way communication.

I don't think the passthru ports on the GDL39 work when dealing with a GDL39 and a 795/796 so be careful there.

You mention a GDU? What device are you calling a GDU?

 

[RV7ator]

Hi, Brian,

Yup, I'm aware of the 795's port 1 restriction for the GDL, and I'm not looking for the passthrough ports to help at all.

The "GDU" is the G3X's GDU370 I'm using as a PFD.

To be certain, you're saying a particular port (specifically on the 795) "in" can be from one device (in this case a 650) and "out" to a different device (the Pro Pilot). Just wanted to be clear on that point besides both needing the same protocol. That would fix my problem except for...

Booting. Here's the manual: "If the GDL39 is powered on with a remote on/off switch, the GDL39 will go into pairing mode automatically for two minutes." Mine's powered on/off remotely when I switch on/off the avionics buss, not using the GDL's pushbutton, yet it doesn't go into pairing mode. Something in the works besides what what the manual says?

John Siebold

 

[g3xpert]

GDL39 Bluetooth Connection with Aera 79X

I buried the GDL on the subpanel since once paired with a 795 it would re-connect each time avionics are powered up. Not so.
John Siebold

Hello John,

Please be sure your software is up-to-date in both the 795 (V3.20) and GDL39 (V2.51).

As Brian says, you should only have to pair your GDL39 once with your 795 and then anytime you power up both units, in any order, they will establish a Bluetooth connection and leap into action.

I do this every day, and sometimes several times a day, with the equipment in my office and with the GDL39 buried in the nose of my plane. It never fails to establish a connection with the 79X without pushing any buttons on the GDL39.

Shoot us an email if you have specific questions.

Thanks,
Steve

 

[Brantel]

Hi, Brian,

1. Yup, I'm aware of the 795's port 1 restriction for the GDL, and I'm not looking for the passthrough ports to help at all.

2. The "GDU" is the G3X's GDU370 I'm using as a PFD.

3. To be certain, you're saying a particular port (specifically on the 795) "in" can be from one device (in this case a 650) and "out" to a different device (the Pro Pilot). Just wanted to be clear on that point besides both needing the same protocol. That would fix my problem except for...

4. Booting. Here's the manual: "If the GDL39 is powered on with a remote on/off switch, the GDL39 will go into pairing mode automatically for two minutes." Mine's powered on/off remotely when I switch on/off the avionics buss, not using the GDL's pushbutton, yet it doesn't go into pairing mode. Something in the works besides what what the manual says?

John Siebold

1. Good, just wanted to be sure you were aware. I would hate to see someone go thru the trouble to change wiring and then find out it won't talk on that port.

2. If you are using the GDL's bare wire cable to talk to the 795, I don't think it will also talk to the G3X at the same time. If you are using BlueTooth for the 795 then it should work since the GDL can talk to two BT and one hardwired device at the same time.

3. If you set the 795 to "AVIATION IN/NMEA & VHF OUT", then yes, the 795 will receive data from a GTN and will send NMEA data to the Trio. Just make sure the baud rate on the TRIO is 9600.

4. The manual says powered on with a remote switch. They are not talking about the switch feeding the bus that the GDL's power wires are connected to. They are talking about the "Remote ON" switch which is an optional switch that turns the device on and off independent of the power inputs. It is the Grey input wire and it is active when tied to ground. You might try connecting it to ground and then powering up your avionics bus. This might cause the unit to go to pairing mode. Not sure however since I can't test that theory right now.

Steve has commented on this forum that Garmin plans to always make the GDL39 boot up in pairing mode. He said it should be in the next revision.

Oh, make sure you have the latest firmware in the 795 and let it update the firmware in the GDL39 if not...