RM510Q w/RM500Q Firmware AT trouble

[Lars Melin]

On 2/4/2021 04:38, Rusty Nails wrote:
> im having an issue in windows and linux/modemmanager with this rm510q.  
> It seems to start up then stop allowing at commands.  any tips on how to 
> resolve this?
> 
> [93736.682684] option1 ttyUSB3: GSM modem (1-port) converter now 
> disconnected from ttyUSB3
> [93736.682723] option 2-2:1.3: device disconnected
> [93736.682853] cdc_mbim 2-2:1.4 wwan0: unregister 'cdc_mbim' 
> usb-0000:00:1d.7-2, CDC MBIM
> [93746.221704] usb 2-2: new high-speed USB device number 27 using ehci-pci

This card draws more current than an USB 2.x (ehci) port can provide 
which is 500mA at best, the card should be used in a USB 3.x port which 
can provide at least 900mA.

You are getting resets and bus drop-outs because of the voltage drops 
which occurs when the card draws more current than the port can provide.

/Lars