Knowledge Base

Call Drop Back

The donor network receives the call from the originating operator and, through the use of an internal database, checks if the number is ported. If the number is marked as ported, then the call is released with a message sent to the originating operator to redirect the call to another operator. The drop back method requires modification to the Donor Operator’s switches to check every incoming call destined for its customers to confirm that the mobile number is ported.

MNP Glossray



Mobile Number Portability.

Donor Operator:

An Operator providing service for a Subscriber's number before Porting.

Recipient Operator:

An Operator providing service for a Subscriber's number after Porting.


The Subscriber shall not be allowed to port out a number for up to sixty calendar days for newly activated numbers or numbers that are ported-in. This period shall be referred to as Minimum Subscription Period (MSP).

667 SMS Service:

The subscriber shall obtain the Name / Primary ID / SIM# information from the Donor operator database by sending text string ‘MNP’ to the designated SMS short-code ‘667’.

Port In Authorization Form:

Porting request form to be filled by subscriber at Recipient operator’s service center or authorized dealer.

Financial Obligation:

The number porting process by the Subscriber requires settlement of financial obligations of the Subscriber towards the Donor operator.

Contractual Obligation:

In case the subscriber has entered in to a contract with the Donor operator, the subscriber shall settle the contractual obligation with the Donor operator before porting request is accepted for porting out by the Donor operator.