Hello Devzone Community,
My name is Ted, and I am continuing work on an nRF9160 based, battery powered custom board firmware. I recently posted a couple of tickets here regarding LTE modem Power Saving Mode (PSM) requesting command, AT+CPSMS. Also asked how to interpret the data returned by both AT+CEREG? and AT%XMONITOR. So far I have limited success seeing my team's 9160 based hardware be granted any active, enabled PSM T3412 timer values. ( Note the info message that appears on Online Profiler when hovering over periodic-TAU entry box. ) I seem only to be able to be granted a 54 minute extended periodic-TAU. This leads to some questions:
Question 1 - is there an AT command sequence prior to, or before and after issuing AT+CPSMS="..." I must use in order to be granted a PSM value?
Question 2 - must an LTE modem have connection with a celular tower or provider in order for AT+CPSMS to be answered, or is a PSM request somehow queued until a celular connection is made?
Question 3 - is it common that a celular provider or Mobile Virtual Network Operator grant only one PSM value?
I find that no matter what extended periodic-TAU value I request, if I am granted anything at all the value granted is invariably 54 minutes. Is this typical, or a sign of my doing something incorrectly?
- Ted
