On the Admin Workstation
Config Manager => Outbound Option => Campaign
Within the Campaign General tab..
In the Dial Setting section there is an option titled "Maximum attempts (1 - 100)"
This setting is defined as follows - Defines the maximum number of attempts that will be made for no answer and busy signal callbacks.
Enter the maximum number of attempts.
Maximum attempts = Zone 1 attempts + Zone 2 attempts / The default is 3.