AT+CUSD=1,"*101#" does not working with two diffence Operator

Question

I'm bulding a program with AT Command to control my Gsm Modem.

My country have 2 operators (VIETTEL and VINAPHONE).

When i push SIM of VIETTEL to GSM Modem (on port COM21), I execute command AT+CUSD=1,"*101#",15

and then, i get result is +CUSD: 2,"STB: 84981057863. TK goc:0d. De biet cac CTKM khac, bam goi *098#.",1

But when i push other SIM of other Operator (VINAPHONE) to this Port (still on port COM21), I also execute same command. And then, i get result is

OK ERROR.

Please help me!!! Sorry because my english is bad.

This is my screen captured: https://anorise.work/SIM.png

Thank you!!!

Answer 1

Try to look at ATD command.

And try ATD"*101#"; and ATD"*101#".