Unlike other services, the call waiting function is reliant on the network. To access the extra call options, you must have an active SIM card put into the phone. If you do not, you may be unable to access them.
Using Call Waiting, a caller who is presently engaged in a call is informed that another caller is attempting to get through to them.
In order to take care of the incoming call, the first call might be put on hold. Call Waiting is being used. Using your mobile phone’s keypad, dial the appropriate code to activate Call Waiting.
The ability to handle many calls at the same time is enabled if call waiting has been engaged.
To enable call waiting, just dial *43# from any phone number.