I need help use 4G Quectel EC20F

IoT Modules LTE Standard Module
1

I use Ec20 4G. I use USSD . AT+CUSD=1,##002# and AT+CUSD=1,**21*Phonenumber# . it respon OK but it returned ok but it didn’t work

2

Hi customer,

  1. Please send ATI and keep result for me.
  2. Could you please confirm if your SIM card supports USSD or not with operator?