Data transfer using VPP in U(SIM)?

IoT Modules Smart Module
1

I am confused about the nature of data transfer through the VPP pin of U(SIM) (pin C6) which is connected to SIM_SWIO (pin A4) of the Reader.
How can a VPP pin transfer data ?
Even if this is a typo,then
Also, How is the U(SIM) operating in this design while only VPP connected to the Reader and data pin of the U(SIM) connected to SC60?
The design I am referring to is
here

2

hi,NormsBreaker:
VPP:programming voltage, //the SIM card’s programming power.In general it is an empty pin in a circuit.
I hope the following documents are helpful to you.
Quectel_SC60_Reference_Design_V1.2.pdf (1.1 MB)

3

I am still confused.
Shouldn’t the VPP pin should be connected to the voltage ?
How is it transferring data ?
How can a voltage pin be used to program the (U)SIM (or anything, for that matter)?

4

hi,NormsBreaker:
you are great! USIM’s VPP pins are not normally used (or dangling pin), so if you have an in-depth understanding of USIM’s VPP, please download the link file and look at it in detail.