Cannot get SIM7600 4G(LTE) working

I have troube to get my shield SIM7600 4G(LTE) working.

I started with the follwong link: https://wiki.dfrobot.com/SIM7600CE-T_4G(LTE)_Shield_V1.0_SKU_TEL0124

I was using an Arduino Uno with no response at all at my AT commands. I have tried it with either pin 7/8 and pin 0/1 connected to Rx and Tx

I used the code I found in the link

I moved away from my arduino and tried it standalone via the usb port. No success. 

Now I have connected the usb port of the shield to a powersupply and a serial debugger via  CP2102 USB to TTL converter. Connect the Rx, Tx and Gnd pin to the appropiate pins on the Jumper Cap Interface.

When sending AT I get the following responses:

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~a¤°1%€p

What I am doing wrong?

Can you please guide me to get this shield working.