L831-EA Module Hardware User Manual
Page 30 of 43
5.5.1 USIM Pins
Pin#
Name
Type
Description
36
UIM_PWR
O
USIM power supply signal
30
UIM_RESET
O
USIM Reset signal
32
UIM_CLK
O
USIM clock signal
34
UIM_DATA
I/O
USIM data signal
66
SIM_DETECT
I
The detection signal for SIM insetting
The default is 390K ohm resistance pulled up and
input.
High level: SIM is present.
Low level: SIM is absent
5.5.2 Description of USIM
5.5.2.1 “Normally Closed
”
SIM Circuit Design
Referenced Circuit Design:
Figure5- 7 Reference Design of “Normally Closed” SIM Card Interface
Normally closed SIM Connector:
1
）
Pull out SIM card, pin 7 and pin 8 short-circuit .
2
）
Insert SIM card, pin 7 and pin 8 disconnect.
