A cold reset of the SIM card during 3V period

Question:

After power up, the UIM voltage stabilizes on 3volts for about 258ms afterwards the voltage drop to 0 volts for about 16ms and then it returns to stabilize on 3volts. Why it is dropping the voltage to 0 for 16 ms?
Is this is the expected behavior?




Answer:

When UE changes an invalid UIM instruction class to a valid one, UE does a cold reset of the card at the same voltage level.

For example, below is IT3 log:

APDU Time: 76.05348958 s
TPDU Time: 76.05348958 s
Header [CLA INS P1 P2 P3]:
00 A4 00 04 02 // invalid instruction class
Incoming data (0 bytes):
-
Outgoing data (0 bytes):
-
Return code [SW1 SW2]:
6A 86
Power off 76.0561224 s
Cold reset 76.09007934 s

ATR
PPS change

APDU Time: 76.1826434 s
TPDU Time: 76.1826434 s
Header [CLA INS P1 P2 P3]:
A0 A4 00 00 02 // valid instruction class
Incoming data (2 bytes):
7F 20
Outgoing data (0 bytes):
-
Return code [SW1 SW2]:
9F 1A

This is an expected behavior.