Service Guide

Table Of Contents

LTE-A Module Series

EM060K-GL&EM120K-GL_Hardware_Design 36 / 78

1. Hot-plug function is invalid if the configured value of <insert_level> is inconsistent with hardware

design.

2. The underlined value is the default parameter value.

3. USIM1_DET and USIM2_DET are pulled low by default, and will be internally pulled up to 1.8 V by

software configuration only when (U)SIM hot-plug is enabled by

AT+QSIMDET

4.1.3. Normally Closed (U)SIM Card Connector

With a normally closed (U)SIM card connector, USIM_DET pin is normally shorted to ground when there

is no (U)SIM card inserted. (U)SIM card detection by high level is applicable to this type of connector.

After executing AT+QSIMDET=1,1 to enable the (U)SIM hot-plug: when a (U)SIM card is inserted,

USIM_DET will change from low to high level; when the (U)SIM card is removed, USIM_DET will change

from high to low level.

 When the (U)SIM is absent, CD is short-circuited to ground and USIM_DET is at low level.

 When the (U)SIM is present, CD is open from ground and USIM_DET is at high level.

The following figure shows a reference design of (U)SIM interface with a normally closed (U)SIM card

connector.

Module (U)SIM Card

Connector

USIM_DET

USIM_DATA

USIM_CLK

RST

CLK

USIM_VDD

USIM_RST

VCC

GND

VPP

GND

TVS array

NOTE: All these resistors, capacitors and ESD should be close to (U)SIM card connector in PCB

layout.

10-20K

22R

33 pF

100 nF

Figure 14: Reference Circuit for Normally Closed (U)SIM Card Connector

4.1.4. Normally Open (U)SIM Card Connector

With a normally open (U)SIM card connector, CD1 and CD2 of the connector are disconnected when

there is no (U)SIM card inserted. (U)SIM card detection by low level is applicable to this type of connector.

After executing AT+QSIMDET=1,0 to enable the (U)SIM hot-plug function: when a (U)SIM card is

inserted, USIM_DET will decrease from high to low level; when the (U)SIM card is removed, USIM_DET

will increase from low to high level.

NOTE