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G3X: splitting RS-232 Tx/Rx Functions

L

lr172

Well Known Member
Does anyone know if the G3X allow you to discretely assign the Tx and Rx sides of an RS-232 port for different functions of are they assigned jointly by port? If the former, can the baud rates be different? For example, can I assign port 1 TX to my SL-40 and port 1 Rx to my 430?

I haven't been able to find this in the manual yet.

Thanks,

Larry
 
Generally speaking, RS232 in and out ports can be assigned different protocols (NMEA, ADSB+, etc) but both need to be at the same baud rate.
 
lr172 said:
Does anyone know if the G3X allow you to discretely assign the Tx and Rx sides of an RS-232 port for different functions of are they assigned jointly by port? If the former, can the baud rates be different? For example, can I assign port 1 TX to my SL-40 and port 1 Rx to my 430?

I haven't been able to find this in the manual yet.

Thanks,

Larry
Click to expand...

BobTurner said:
Generally speaking, RS232 in and out ports can be assigned different protocols (NMEA, ADSB+, etc) but both need to be at the same baud rate.
Click to expand...


The G3X does not allow you to assign different protocols to the Tx and Rx side of a given RS-232 port. You have to pick one of the options and that sets both directions on the port.

However, there are some COMBO protocols available like:
  • Aviation In/NMEA & VHF Out
  • TIS-A In/NMEA & VHF Out
These add a bit of flexibility.

This area is covered starting on page 34-107 of rev AF of the install manual.

Let us know what you have as far as equipment goes and what you are trying to do and maybe we can help you figure out your options.
 
Brantel said:
The G3X does not allow you to assign different protocols to the Tx and Rx side of a given RS-232 port. You have to pick one of the options and that sets both directions on the port.

However, there are some COMBO protocols available like:
  • Aviation In/NMEA & VHF Out
  • TIS-A In/NMEA & VHF Out
These add a bit of flexibility.

This area is covered starting on page 34-107 of rev AF of the install manual.

Let us know what you have as far as equipment goes and what you are trying to do and maybe we can help you figure out your options.
Click to expand...

Thanks Brian. Trying to conserv ports. Have two GDU 370's and need to connect the following

GSU 25 AHRS (2 way)
GMC 305 (2 way)
SL-40 (Tx only)
GNC 430W (Rx only)
GDL-39 (2 way)

With this config, I am bumping up on my 6 ports and would like a spare available.

Does the 430W use Aviation or MapMX. If the former, it seems that the option you mentioned would work for sharing a port between the two radios, but I vaguely remember that this is supposed to be mapmx.

Larry
 
lr172 said:
Thanks Brian. Trying to conserv ports. Have two GDU 370's and need to connect the following

GSU 25 AHRS (2 way)
GMC 305 (2 way)
SL-40 (Tx only)
GNC 430W (Rx only)
GDL-39 (2 way)

With this config, I am bumping up on my 6 ports and would like a spare available.

Does the 430W use Aviation or MapMX. If the former, it seems that the option you mentioned would work for sharing a port between the two radios, but I vaguely remember that this is supposed to be mapmx.

Larry
Click to expand...


GSU 25 AHRS (2 way) Uses Garmin Instrument Data to the PFD Serial Port 1 of 3 (backup to the CAN Bus)
GMC 305 (2 way) Uses Garmin Instrument Data on the PFD Serial Port 2 of 3 (if you trade up to a 507 now, you can use CAN Bus and free up a serial port)
SL-40 (Tx only) Uses Garmin VHF Com on the MFD Serial port 2 of 3 ( I put this on the MFD because that is likely where you will be trying to push frequencies from)
GNC 430W (Rx only) Uses MAPMX on PFD Serial Port 3 of 3
GDL-39 (2 way) Uses Garmin Data Transfer on the MFD Serial port 1 of 3 (this one must be connected to either port 1 or port 2 or the MFD per the manual)

That leaves MFD serial port 3 of 3 as a spare. Double check my suggestions and I would also run it by G3XPERT just in case there are any constraints I have not considered.
 
Brantel said:
GSU 25 AHRS (2 way) Uses Garmin Instrument Data to the PFD Serial Port 1 of 3 (backup to the CAN Bus)
GMC 305 (2 way) Uses Garmin Instrument Data on the PFD Serial Port 2 of 3 (if you trade up to a 507 now, you can use CAN Bus and free up a serial port)
SL-40 (Tx only) Uses Garmin VHF Com on the MFD Serial port 2 of 3 ( I put this on the MFD because that is likely where you will be trying to push frequencies from)
GNC 430W (Rx only) Uses MAPMX on PFD Serial Port 3 of 3
GDL-39 (2 way) Uses Garmin Data Transfer on the MFD Serial port 1 of 3 (this one must be connected to either port 1 or port 2 or the MFD per the manual)

That leaves MFD serial port 3 of 3 as a spare. Double check my suggestions and I would also run it by G3XPERT just in case there are any constraints I have not considered.
Click to expand...

Yes, this looks good. In a pinch, you can also just connect the GMC 305 to the roll servo and not to a display.

It is nice to have the backup data bus from the GMC 305 to the display, but the most important link is the one from the GMC 305 to the roll servo which allows you to engage the autopilot even when the displays are unavailable.

Thanks,
Steve
 
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