Scan sequence on BG96

Hi all,

I have a question about the LTE/GSM selection on the Quectel BG96. I have been working on the modem for a while. Recently we have tested that the probability that the modem selects LTE or GSM is about 50:50, even though we have set the RAT priority sequence on the modem to “First LTE and then GSM”. The sequence is set by AT command “nwscanseq”.

I have found some slide from Quectel that the RAT/network combination can be selected randomly as long as the link quality is above some threshold. My question is that what is then the purpose of setting “RAT Sequence” on the modem if they are randomly selected? When will such setting take effect and select the LTE before GSM?

In our tests, the LTE coverage is usually better than GSM and the connection with LTE is more stable. But then we need to develop our own LTE/GSM selection procedure to select LTE when both LTE and GSM ara available, to avoid modem to accidentally select GSM? Is this a common practice for Quectel modem (BG96)?

Really looking forward to getting some answer here. Thanks!

if you send at cmd " AT+QCFG=“NWSCANSEQ”,00 “ , RPLMVACT have been change to NULL , so the scan order will followe the order save in sim card file ( EFS rat_acq_order)

submit two option for you reference

.solution :

option 1: contact with sim card vender ,and changer the file of EFS rat_acq_order to CATM- GSM

option 2 : do not send AT , " AT+QCFG=“NWSCANSEQ”,00 “, if so the RPLMNACT will be kept .

for the detail pls refter to the doc of “Quectel_BG95&BG77_Network_Searching_Scheme_Introduction_V1.0.pdf”