Your existing SIM card can be activated to use 3G service connection by just sending the SMS to respective network for request of activation. Here is the setup guide for 3G services for India telecom services. Always choose best network for your 3G services.
Now almost each and every new SIM card is having pre-activated 3G service, so no need to send request for services. This request application is only for existing customers.
Note: You must have 3G enabled mobile phone during activation request.
Step: Send a message to customer care 121 with keyword 3G. You will get a confirmation message with in 5 minutes and then just restart the phone. Your 3G service will be activated.
Step: You have to send message request using Vodafone sim card inserted in 3G enabled phone. Just message ACT 3G to 111. You will receive a confirmation message on activation of service
Step: You have to send SMS request to Idea Cellular though your existing SIM card for activation. For that type message ACT 3G send to 12345 or alternatively you can type 3G send it to 54777. Your request will be approved and 3G will be activated soon.
Step: You have to send message ACT 3G to 53333 or alternatively you can send message 3G Life to 53333 with your 3G enabled phone. Your service will be get activated within 4 hours of request.
Step: For Aircel customers, you have to send ACT 3G to 121, and get your existing SIM card 3G service activated.
Note and Conclusion:
Don’t forget to restart your mobile phone after you receive confirmation message.