Try these campaign settings:
Dial timeout = decrease e.g. 25 seconds
Drop Call seconds = 0
Auto Dial Level Threshold = DISABLED
Available Only Tally = N
Available Only Tally Threshold = DISABLED
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Other interesting settings, which will change your dial "speed":
System settings (leave the default setting at 40)Max FILL Calls per Second -This setting determines the maximum number of calls that can be placed by the auto-FILL outbound auto-dialing script on for all servers, per second. Must be from 1 to 200. Default is 40.
Server settings:Max Trunks --> change it according to your carriers maximum concurrent lines
Max Calls per Second --> don't go over "4" otherwise your carrier could be pissed off and won't complete your calls
Vicibox 6.0.2 from Vicibox_v.6.0.x86_64-6.0.2.iso | Vicidial 2.12-560a build: 160617-1427 | Asterisk 1.8.32.3