> 3.3 | Power Saving

> SLEEP mode reduces the functionality of the module to a minimum and, thus, minimizes the current consumption to the lowest level. SLEEP mode can be set with the AT+CFUN command which provides the choice of the functionality levels <fun>=0, 1, 5, 6, 7, 8 or 9. For further details on power saving and the functionality levels supported by your Siemens product see [1] and [2].
> If the module is in multiplexer mode, it is not recommended to activate SLEEP mode with AT+CFUN=<n>. For products supporting Multiplexer Protocol version 3, the best approach to properly control SLEEP mode in this case is to issue the PSC messages described in Section 4.3.10.