LTE Standard Module Series
EC20 R2.1 Mini PCIe Hardware Design
EC20_R2.1_Mini_PCIe_Hardware_Design 29 / 51
V
IL
≤0.5V
V
IH
≥2.3V
VCC_3V3
≥150ms
Resetting
Module
Status
Running
PERST#
Restart
≤460ms
Figure 12: Timing of Resetting Module
3.10.5. LED_WWAN# Signal
The LED_WWAN# signal of EC20 R2.1 Mini PCIe is used to indicate the network status of the module,
and can absorb a current up to 40mA. According to the following circuit, in order to reduce the current of
the LED, a resistor must be placed in series with the LED. The LED is emitting light when the
LED_WWAN# output signal is low.
LED_WWAN#
VCC
R
Figure 13: LED_WWAN# Signal Reference Circuit Diagram
There are two indication modes for LED_WWAN# signal to indicate network status, which can be
switched through following AT commands:
AT+QCFG="ledmode",0
(Default setting)
AT+QCFG="ledmode",2
The following tables show the detailed network status indications of the LED_WWAN# signal.
Table 15: Indications of Network Status (AT+QCFG="ledmode",0, Default Setting)
Pin Status
Description
Flicker slowly (200ms Low/1800ms High)
Network searching