L80 Baurate change - not durable?

I have a Quectel L80 Module earlier set to 4800 Bd. It have worked stable with this baudrate over years. Now I want to change it back to 9600 Bd. I use the command “$PMTK251,9600*17” with CR-LF on end. To send it I use the terminal program Hterm. The command make the L80 working with 9600 Bd - all seems o.k. But if I switch the power off the L80 and switch on the baudrate is 4800 Bd again. The L80 seems to guess the 9600 Bd change if power off. What I have to do to get the 9600 Bd stable after switch off and on the power.
Thank you very mutch for help.
Best Regards from Germany

Now I have found the solution - this (new) command set the Baudrate durable:

But the command $PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29
is not durable too. Is there a similar command which durable saves the output only for RMC?

Hallo gzielos,

  1. Yes, changes made by PQ commands can be saved after a power outage. (Changes via PMTK commands will not be saved.)
  2. So far we don’t have PQ command for NMEA output configuration, it has to be reset after a complete power outage. However, it’s recommended to keep V_BCKP powered (e.g. with a battery), thus the configuration will not be changed by a restart or switch off.

Liebe Grüße aus China,

1 Like

Hallo Meiji,
thank you for the hints - thank you for the greetings in German too. It is a pitty that we have not PQ commands for some funktions. Is there a hope to get a PQ command for NMEA output configuration? I will realize a minimal GPS long time tracker with L80 and OpenLog from sparkfun. This OpenLog uses the serial communication to save the serial data from L80 on a µSD card. For this is the GRMC sentence sufficient.
Liebe Grüße aus Deutschland

Hallo Gunther,

We will internally evaluate if we can add PQ commands for NMEA output configuration. We will update you as soon as we get the feedback.

Liebe Grüße

Hi @gzielos ,

We will add a PQ command for NMEA configuration. It’s in progress.

Best regards

Hi @gzielos ,

We’ve developed the PQ command for NMEA configuration, it’s currently the beta-version. Please find the corresponding documentation and firmware via your private message.

Best regards

Hello Meiji,
there are some problems to use the $PQNMEARATE command. I try to change the NMEA sets to $PQNMEARATE,W,0,1,0,0,0,0*7E
(only the RMC sentence).
But the result is:


There is no answer to $PQNMEARATE,W,0,1,0,0,0,0*7E and no reaction,
there is nothing! What shell I do??? Please help me
Best Regards

Dear Sir,
Please make sure you have successfully updated L80GR01A11S_BETA0401.
My set-up after upgrading that BETA0401 version:
$PQVERNO,R3F // query version if upgrade success.
7A //query current para…
$PQNMEARATE,W,0,1,0,0,0,07E //disable other messages (in list) except RMC.
23 //disable $GPTXT message.
Please refer to my log(please change its extension from .zip to .txt):
Log-L80GR01A11S_BETA0401.zip (48.5 KB)

Also attached the latest protocol doc:
Quectel_Lx0&Lx6&LC86L&LG77L_GNSS_Protocol_Specification_V2.1 (1).pdf (525.1 KB)


Hello Berton Peng,
thank you for the hints. I have questions:
All my problems are with L80 - is the upgrating really for L80?
How can I realize the upgrade, what tools I need?
thank you again and greetings from Germany
Gunther Zielosko

Dear Sir,
Please ensure that you module is L80 instead of L80-R which is a ROM version and doesn’t support PQ commands.
Regarding to upgrade for L80:
1, you could use PC tool FlashTool_exe_v4.1.0.rar to upgrade and refer to EVB User guide.
Quectel_L80&L80-R&L86&LC86L_EVB_User_Guide_V2.0.pdf (2.7 MB)
Flashtoolv4.0.zip (547.4 KB)