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MANUAL
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2.3.5 SIM Interface
This section pertains to the external SIM-interface. Switching between the internal and external SIM-interface is
done through the AT*ESSE-command. It is possible to get a phone module that includes an eight meter cable
driver. This driver requires some external circuitry. This feature and its requirements are described in a separate
document; see “Related Documents” in chapter 1.
•
SIMVCC
•
SIMRST
•
SIMCLK
•
SIMDATA
•
SIMDET
This SIM interface allows the use of 3 V and 5 V SIM cards. By default it works on 3 V levels but will automatically
switch to 5 V, if a 5 V SIM card is fitted.
SIM voltage levels, as shown in the following table, are dependent on the type of SIM card detected by the module.
2.3.5.1 SIMVCC
The SIMVCC is the supply voltage for an external SIM. The module will first try to communicate using 3V supply
voltage. If it fails it will switch to 5V and retry to communicate.
Note:
If the phone module includes the eight meter SIM-cable driver, there is no upper limit of the source current
on SIMVCC. Shorting SIMVCC will in this case permanently damage the module.
Limits
Parameter
Symbol
Conditions
Min.
Nom.
Max.
Unit
3V mode
2.7
3.0
3.3
Volt
Voltage level
V
out
5V mode
4.5
5.0
5.5
Volt
3V mode (no driver)
6
mA
Load current
I
dc
5V mode (no driver)
10
mA
t=200ns (no driver)
200
mA
Pulsed output current
I
peak
t=400ns (no driver)
100
mA
Table 14: SIMVCC Electrical Parameters
2.3.5.2 SIMRST
The SIMRST output from the module is an active low reset signal.
Limits
Parameter
Symbol
Conditions
Min.
Nom.
Max.
Unit
3V mode
0.35
Volt
Low level output
voltage
V
OL
(I
O
=-200
μ
A)
5V mode
0.3
Volt
3V mode
2.4
Volt
High level output
voltage
V
OH
(I
O
=+20
μ
A)
5V mode
4.4
Volt
Rise and fall time
t
r
/ t
f
400
μ
s
Table 15: SIMRST Electrical Parameters
