Product Info

LTE Module Series
EG21-G Hardware Design
EG21-G_Hardware_Design 30 / 100
Figure 5: Sleep Mode Application with RI
 Sending data to EG21-G through USB will wake up the module.
 When EG21-G has a URC to report, RI signal will wake up the host.
3.5.1.4. USB Application without USB Suspension Function
If the host does not support USB suspension function, USB_VBUS should be disconnected via an
additional control circuit to let the module enter into sleep mode.
 Execute AT+QSCLK=1 command to enable the sleep mode.
 Ensure the DTR is held at high level or keep it open.
 Disconnect USB_VBUS.
The following figure shows the connection between the module and the host.
USB_VBUS
USB_DP
USB_DM
AP_READY
VDD
USB_DP
USB_DM
GPIO
Module Host
RI
EINT
Power
Switch
GPIO
GND
GND
Figure 6: Sleep Mode Application without Suspension Function
Switching on the power switch to supply power to USB_VBUS will wake up the module.
Please pay attention to the level match shown in dotted line between the module and the host. For more
details about EG21-G power management application, please refer to document [1].
3.5.2. Airplane Mode
When the module enters into airplane mode, the RF function does not work, and all AT commands
correlative with RF function will be inaccessible. This mode can be set via the following ways.
NOTE