Number Utilization Guide

Best practices to improve call connectivity, reduce spam flagging, and ensure regulatory compliance while using Vobiz infrastructure.

1Choosing the Right Number Series

Selecting the appropriate number series significantly impacts pickup rates and compliance.

Standard High-Connectivity

79 Series – Gujarat
80 Series – Karnataka
22 Series – Mumbai
11 Series – Delhi

79 and 80 series numbers generally show higher connectivity as they resemble standard mobile formats and appear familiar to end users.

Specific Use Cases

BFSI Compliance

Use 1600 Series numbers for BFSI-related services to remain compliant.

Promotional / Marketing

Use 1400 Series numbers to stay within regulatory guidelines.

High Pickup Rate

Consider 92 Series numbers for improved pickup rates.

2Daily Call Volume Best Practices

To prevent spam flagging and maintain number health:

Avoid exceeding 500–600 calls per number per day.
Distribute calls evenly between 9:00 AM and 9:00 PM.

Avoid sudden traffic spikes on newly provisioned numbers.
Do not concentrate large volumes within short time windows.

Caution: Overstressing a number increases the likelihood of spam classification by carriers and third-party apps.

3Warm vs Cold Calling

"Connectivity is significantly higher when calls are warm leads with existing relationships."

Higher Connectivity Indicators

✓ Existing relationship / prior interaction
✓ Call duration exceeds 1–2 minutes
✓ Natural and meaningful conversations

Risk of Spam Detection

✕ Cold calling without opt-in
✕ Repetitive dialing patterns
✕ Short-duration calls ("hang-ups")

4Number Rotation Strategy

Proactive rotation maintains "number health" and prevents burnout.

Daily Limit

Use a specific number once per day where possible to avoid repetitive ID patterns.

DID Rotation

Rotate between multiple DIDs (Direct Inward Dialing) on alternate days.

Cooling Period

If a number is flagged, pause usage for approximately one week before reattempting traffic.

5Spam Recovery Best Practices

Pause Traffic: Temporarily stop outbound usage on the flagged number.

Legitimate Use: Use the number internally for 5–10 legitimate calls with 3-5m duration.

Update Identity: Refresh caller ID information in Truecaller or similar registries.

Gradual Reuse: Slowly reintroduce outbound traffic to verify classification status.

6Routing & Infrastructure Optimization

Vobiz uses AI-optimized routing to provide the best possible connection quality:

Improve call connection stability

Reduce spam exposure patterns

Optimize network paths dynamically

Improve delivery consistency

Note: Routing optimization alone cannot compensate for high-volume abusive patterns. Responsible usage is critical.

7Key Compliance Reminders

1Use 1600 series for BFSI communication.
2Use 1400 series for promotional campaigns.
3Avoid random or scraped lead databases.
4Ensure opt-in consent where required.
5Maintain controlled and predictable calling patterns.

8High-Volume Warm Calling Guidelines

"If you are running warm call campaigns (existing customers, verified opt-ins, verified prior interaction), higher daily call volumes can be supported safely."

Permitted Volume

Daily volumes of 1,000 to 10,000 calls per number may be executed for verified warm leads.

Window Management

Calls must be distributed evenly across the 9:00 AM – 9:00 PM window. Avoid burst dialing.

Sustainable Success

Success is sustainable only when lead data is verified and recipients are familiar with your brand.

Natural Patterns

Maintain meaningful call durations and natural conversation flows to signal legitimacy to carriers.

Important: Aggressive cold dialing at high volumes may result in increased spam flagging and reduced number health. Always prioritize lead quality and opt-in status.

Additional Resources

Vobiz Dashboard

Sustainable call performance is achieved through balance.

Following these guidelines ensures long-term number health and maximum connection rates for your communication stacks.

Best Practices