AT QLTS doesn't work on network different from SIM card

Hi support,

I have recently run into a problem with AT+QLTS command when connecting to different network.

My modem is the EC21-A and I’m currently using an AT&T Sim card. AT+QLTS works fine when it’s connected to AT&T but when I manually switch it to a different network, Movistar, then AT+QLTS command only returns an OK and is missing the timestamp. Note that I set the modem to roaming mode and I can still connect to an APN as well as getting the proper return from AT commands such as ATI, AT+CEREG?, AT+COPS?, AT+CSQ, AT+QLTS. I then switched the SIM card to a Movistar and I have no problem with the AT+QLTS command.

From the manual, AT+QLTS command would “Obtain the Latest Time Synchronized Through Network” so does this means that it’s working as intended and the command doesn’t work on a network different from the SIM? If this is the case, is there another way I can obtain the time when I’m on a network different from the SIM Card?

Thank you in advance!

Hello Huy_Dang
If the registration network is normal, AT+QLTS can get the current time. If the return is “”, it is recommended that you execute at+cfun=0 first, then execute at+cfun=1, and then query AT+QLTS after successful network injection, thank you.