Telit FAQs, Part 6: What sleep/low power modes are available on the Telit modules?

There are several sleep/low power modes available, depending on the specific module that you are using. An important point to know is that the module cannot go into sleep mode with the USB connection still active. This is because the VUSB voltage may back-power the device, preventing it from going to sleep. So for an implementation that uses USB, it is recommended to still have access to some of the UART lines that can control sleep mode. If not all the lines, then at least RTS or DTR, which can be used to enter/exit power saving mode.

For a detailed explanation of the power saving features of your module, please see the Telit Software User Guide for your specific module.