dial_prefix

What Dial Prefix Does

A prefix added to the beginning of every outbound dial string before it is passed to Asterisk. Commonly used when calls must pass through an external PBX that requires an outside line access code (e.g., 9) before PSTN numbers. Must match your dialplan configuration.

Recommended Configuration

| Center Size | Recommended Value | Notes |

| --- | --- | --- |

| 10–25 Agents | Varies by PBX config — often 9 or blank | Start conservative, monitor for 48 hours before adjusting |

| 25–100 Agents | Varies by PBX config — often 9 or blank | Scale gradually — larger operations amplify effects of misconfiguration |

| 100–500 Agents | Varies by PBX config — often 9 or blank | Consult ViciStack optimization team for enterprise-scale tuning |

How to Change This Setting

• Go to Admin > Campaigns

• Select campaign

• Find Dial Prefix field

• Enter the required prefix or leave blank for direct SIP dialing

• Test with a known-good number after changes

• Verify Asterisk dialplan matches expected dial string format

• Submit

Common Problems

Double-dialing prefix when both campaign and dialplan add the prefix

Using wrong prefix causes all outbound calls to fail silently

Prefix not needed for direct SIP trunk configurations

ViciStack Module

ViciStack’s Dialer Tuning & Auto-Configuration module automatically monitors and optimizes dial_prefix based on real-time performance data from your operation. Instead of manual tuning, ViciStack continuously analyzes call outcomes, agent performance, and contact rates to recommend and implement optimal values — often catching configuration drift before it affects your numbers.