EG21 AT+QGPSCFG=“outport”,”uartdebug” return ERROR: 501

IoT Modules LTE Standard Module
1

We are using EG21 and trying configure the modem to output a constant NMEA message.
We are trying to redirect NMEA output to uart debug port. but when we try this configuration
AT+QGPSCFG=“outport”,”uartdebug” it will return ERROR:501

when we try other output option like “usbnmea”, or “none”
the command will return OK

Currently we cannot access usb do to hardware limitation.

2

Hi,

Streaming NMEA to uartdebug on the EG21 is most likely not supported in this firmware, which is why you’re getting ERROR:501 (invalid/unsupported parameter).

You can find out the version with these commands.

AT+CGMR
AT+QGMR

Or pull NMEA “on demand” instead of constantly dumping it into the port.

And can you try this command:

AT+QGPSCFG="outport",?

This “test” form lists the supported outputs. If you see uart1, uart2, or uartdebug in the output, NMEA streaming is supported over that UART.

3

We wanted to stream NMEA output to test the GPS signal reception to tune the RF path. If This command is not available in the current version is the NMEA streaming feature available in the latest? Or do we still need to pull it on demand anyway?

4

Hi,

If there’s no UART option listed in the AT+QGPSCFG=“outport”,? list, it’s likely missing from recent versions (at least in public builds).

In rare cases, it might be added in special SKUs/custom builds; in that case, your only recourse is to get clear confirmation from your Quectel FAE that it “supports NMEA out to UART on EG21?” However, in practice, NMEA streaming on EG-/EC-series is mostly targeted over USB.

If USB is disabled, the most practical way is to capture NMEA on-demand and loop it at a rate of 1 Hz on the host side:

Turn on GNSS

AT+QGPS=1

Leave continuous streaming disabled (there’s no UARTDebug anyway), instead, execute the following commands in a 1 Hz loop:

AT+QGPSGNMEA="GSV" // SNR/CN0 and satellite visibility – most useful for RF adjustment
AT+QGPSGNMEA="GGA" // Fix quality, HDOP
AT+QGPSGNMEA="RMC" // Speed/position/time

If you prefer, simply capturing GSV at 1–2 Hz is sufficient when adjusting the RF path. You’ll see the change in CN0 values ​​immediately.

To ensure USB NMEA support, see the supported string/port list with

AT+QGPSCFG="outport",? 
AT+QGPSGNMEA=?