Call Forwarding or Call Diverting is explained.

Call forwarding means diverting an incoming call from your phone to another number. This is also called diverting, which a mobile operator provides as a service.

The service brings more revenue to the mobile operator and provides a significant feature to mobile users. If call forwarding is enabled for a mobile subscriber, then he can receive the original calls on another number. 

For example, if a mobile user moves to another country, where the calls while roaming are very costly. But at the same time, he does not want to miss the important calls on the original number. He buys a new sim card, local to the roaming country, and enables call forwarding to the original number. 

Call forwarding provides more revenue to mobile network operators. Now, there are two calls in place of one. While doing call forwarding, there are two call legs, one from the original mobile to the called party and another form called party to the forwarded number.

What is Call transfer?

The call is sent to a new number other than the originally dialed number in both, but they are different. In the call transfer, the original call is put on hold. The new number is dialed, and once the call on a new number is picked, the two calls are bridged. The call transfer does not need any settings in the profile of the mobile subscriber on HLR.

In the Incall transfer, there is only one leg for the call. So this leads to no additional revenue for the mobile operator. You might experience call transfer when called in some company office. In the company office at reception, the guy picks up the call and connects you to the desired person. And the reception guy gets disconnected from the call.

What are the Call forwarding types?

A mobile subscriber has flexibility for call forwarding type. The feature may be active for different scenarios. During roaming, a mobile subscriber may lose the signal. So he wants to set the call forwarding to his landline number if the phone is unreachable. Following is the list of call forwarding types.

Call forwarding unconditional type.

As the name suggests, if the call forwarding or call diverting for unconditional is set, all incoming calls will be forwarded to the other number. The calls will be forwarded even if a mobile subscriber is online.

Unconditional call forwarding is useful when you know the original phone will not be used. In case you have purchased a new number and want to update a new one to all of your contacts. But meanwhile don’t want to lose the calls from the older phone number.

Call forwarding conditional type.

When conditional call forwarding is enabled, call diverting depends on subscriber status. Following are the conditional call diversion scenarios.

Call forwarding busy:

A mobile user is talking to another person. In this, the status of the user is busy. At a single time, the user can receive only one call. If the call forwarding busy is not active, the new call will disconnect.

Call forwarding not reachable:

In situations where mobile phones get disconnected from the network. Call forwarding is not reachable is set. Then the forwarded number will start ringing.

Call forwarding no answer:

The phone keeps ringing for some time for an incoming call, and the call is not picked up. Now, this call forwarding comes into the picture. If a mobile subscriber has activated this call forwarding, then after ringing for some time call forwards to the forwarding number.

Call forwarding data on HLR:

Like any other service, the subscriber profile on HLR has a call-forwarding subscription for each call-forwarding type. With the subscriber provisioning, call forwarding is in the registered state. Later a subscriber can turn each call forwarding type on or off. The following are the parameters in the subscriber profile. All types are described in GSM 03:08.

  1. Call forwarding type.
  2. Call forwarding state.
  3. The number for forwarding.