PSM is a 3GPP-defined low-power state in which the UE remains registered to the network but stops monitoring the paging channel, allowing long battery-saving sleep periods between user-initiated activity bursts.
PSM is requested through AT+CPSMS. The <mode>
parameter controls whether PSM is enabled (1), disabled (0),
or disabled with a parameter reset (2).
Network constraints
The network sets the granted timer values and may reject PSM entirely. Operator-specific minimums may also apply, such as a minimum T3412 of 190 minutes.
References
See 3GPP TS 23.682 for the PSM feature definition and 3GPP TS 24.008 for the timer
encoding. The nRF93M1 AT Command Manual documents the full +CPSMS
syntax.