We are using a number of XB3M1 on the Verizon network. As of Firmware 11417 and prior, we never seem to get any other value other than 0x45 or 0x46. Any ideas on this? We are using the DB AT command wrapped in an API request.
The DB value reports the RSSI as it is reported by the tower.
Is this information in the datasheet somewhere? I see an option to view uncached, but the frame generation tool doesn’t like parameters on DB.
Additionally, the ATDB value is an RSSI reading, and RSSI is not a particularly useful measurement on LTE networks. You can use ATSQ and ATSW instead, to retrieve RSRP and RSRQ values.
https://www.digi.com/support/knowledge-base/understanding-lte-signal-strength-values
(XBee Cellular devices do not SNR readings.)
What information are you referring to? The SQ and SW commands certainly are in the user guide: https://www.digi.com/resources/documentation/Digidocs/90002258/#reference/r_cmd_sq.htm
As for the frame generator, the parameter needs to go in the “Parameter value” field. To send DB 1, for example, the frame you want is along the lines of 7E 00 05 08 01 44 42 01 6F.
DB is a read only value. It is not a settable command. If you are using the API frame generator, then the ‘Parameter value’ field is where you specify the parameter. Only the command name (DB) is provided in the ‘AT command’ field.
My mistake was trying to send an ascii 1 instead of 0x01. As to being a read only value, yes, but db has a parameter, see newer datasheets.
Newer datasheets show a parameter on DB which allows reading the uncached rssi value. This shows a changing usable value. The cached value would appear to default to some value on startup and never change.
My response is not about SQ and SW, rather about the answer that “RSSI is reported by the tower”. If this is so, I don’t see it in the XB3 datasheet, although I suppose it could be in the cellular modem datasheet or other reference material.
Do you see RSSI reading changes if you put, for example, a 10dB RF attenuator, on the antenna connection? I can clearly see the effect of a signal attenuator, therefore I have to believe the DB command works.
As others have already pointed out, the RSSI is pretty much useless in the LTE technology. RSRP and RSRQ are better indicators.