LTE-A Module Series
EM12-G Hardware Design
EM12-G_Hardware_Design 38 / 62
3.10.2. WWAN_LED# Signal
The WWAN_LED# signal is used to indicate the RF status of the module, and its typical current
consumption is up to 40mA.
In order to reduce the current consumption of the LED, a resistor must be placed in series with the LED,
as illustrated in the figure below. The LED is ON when the WWAN_LED# signal is at a low voltage level.
WWAN_LED#
VCC
R
Figure 20: WWAN_LED# Signal Reference Circuit Diagram
The following table shows the RF status indicated by WWAN_LED# signal.
Table 13: Network Status Indications of WWAN_LED# Signal
3.10.3. WAKE_ON_WAN# Signal
The WAKE_ON_WAN# signal is an open collector signal, which requires a pull-up resistor on the host.
When a URC returns, a 1s low level pulse signal will be outputted to wake up the host. The module
operation status indicated by WAKE_ON_WAN# is shown as below.
Table 14: State of the WAKE_ON_WAN# Signal
WWAN_LED# Level
Description
Low Level (LED ON)
RF function is turned on
High Level (LED OFF)
RF function is turned off if any of the following circumstances occurs:
The (U)SIM card is not powered
W_DISABLE1# signal is at low level (airplane mode enabled).
AT+CFUN=4
(RF function disabled)
WAKE_ON_WAN# State
Module Operation Status
Output a 1s low level pulse signal
Call/SMS/Data is incoming (to wake up the host)
Always at high level
Idle/Sleep