RAK7258 LTE RSSI values

Hi I’m trying to track down lost packet to LNS over cellular backhall
The status page has the following

Network: FDD LTE
RSSI: 18 to 15

  1. Is there a table the converts this value (18 etc) to a meaningful RSSI value?
    I took at look quectel AT+CSQ docs and 18 = -77 15 = -83 for most LTE tables is Fair connection
    UI gives it 2 bars

  2. Can the quectel modem be accessed via AT cmds from cmd line?
    Or is there a utility I can use?

  3. how often is the status page updated ?

Thanks
Lawrence