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Choosing the Right Phone Number for Your Business Messaging Needs

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In today’s communication landscape, businesses use different types of phone numbers to connect with their customers. Azure Communication Services (ACS) supports several types of numbers across various regions, each suited to specific use cases. This document will help you understand the types of numbers ACS offers, where they’re available, and how to select the most appropriate type for your business needs.

Number Types with SMS Capabilities Supported by ACS

Azure Communication Services provides the following phone number types:

  • Toll-Free Numbers
  • 10DLC (10 Digit Long Code)
  • Short Codes
  • Alphanumeric Sender IDs

Toll-Free Numbers

  • Availability: United States, Puerto Rico, Canada
  • Status: Generally available
  • Description: Toll-free numbers allow customers to contact a business without incurring charges.
  • Format: 1-800-XXX-XXXX or 1-888-XXX-XXXX.
  • Use Cases:
    • Customer Support: Encourages customers to reach out without worrying about charges.
    • Notifications and Alerts: Ideal for sending notifications, alerts, and confirmations in NOAM.
  • Regulations:
    • Toll-free numbers used for messaging require toll-free verification.
    • Opt-Out Management: Businesses must support opt-out keywords (e.g., STOP, UNSUBSCRIBE) and manage customer requests to stop receiving messages.
  • Purchase eligibility: Check subscription and location eligibility here.

10DLC (10-Digit Long Code)

  • Availability: United States
  • Status: Public Preview
  • Description: 10DLC refers to 10-digit local numbers regulated for business A2P (Application-to-Person) messaging.
  • Format: XXX-XXX-XXXX.
  • Use Cases:
    • Local Business Communication: Builds a local presence within the US.
    • Marketing & Promotions: Compliant promotional messaging.
    • Appointment Reminders: Transactional messages, order confirmations, etc.
  • Regulations:
    • Requires 10DLC campaign registration in the US for compliance.
    • Opt-Out Management: Businesses must handle opt-out requests (e.g., STOP) to comply with US regulations.
  • Purchase eligibility: Check subscription and location eligibility here.

Short Codes

  • Availability: United States, United Kingdom, and Canada
  • Status: Generally available
  • Description: Short codes are 5-6 digit numbers ideal for high-volume messaging.
  • Format: Short codes are 5-6 digit long. Example: 12345 or 678910
  • Use Cases:
    • High-Volume Campaigns: Product launches, flash sales, and voting campaigns.
    • Two-Factor Authentication (2FA): Secure and quick response times.
    • Customer Engagement: Polling, contests, and interactive campaigns.
  • Regulations:
    • Requires carrier approval; usage is subject to carrier and industry guidelines.
    • Opt-Out Management: Businesses must provide clear opt-out instructions (e.g., "Reply STOP to unsubscribe").
  • Purchase eligibility: Check subscription and location eligibility here.

Alphanumeric Sender IDs

  • Availability: Austria, Denmark, Estonia, France, Germany, Ireland, Latvia, Lithuania, Netherlands, Poland, Portugal, Spain, Sweden, Switzerland, Australia, Czech Republic, Finland, Italy, Norway, Slovakia, Slovenia, United Kingdom.
  • Status: Generally available Description: Allows sending SMS messages using a custom name (business or brand name) as the sender.
  • Format - Alphanumeric Sender IDs can contain up to 11 characters (letters and/or numbers). Example: CONTOSO, CONTOSOAlert
  • Use Cases:
    • Brand Recognition: Enhances brand visibility directly in the message sender field.
    • Notifications: Order updates, delivery notifications, and account-related messages.
    • Marketing: Commonly used for branding in EMEA/APAC.
  • Regulations
    • Some countries require registration for using alphanumeric sender IDs.
    • Opt-Out Management: While Alphanumeric IDs are typically one-way, businesses should still provide opt-out instructions in the message content.
    • France: Alphanumeric IDs are permitted only for transactional messaging, not marketing.
    • Australia: Alphanumeric Sender IDs are permitted, but opt-out instructions should be provided.
  • Limitations: Does not support receiving responses; subject to local regulations.
  • Purchase eligibility: Check subscription and location eligibility here.

Choosing the right number type for your business

Factor Toll-Free Number 10DLC (10-Digit Long Code) Short Code Alphanumeric Sender ID
Geographic Target United States, Canada United States United States, United Kingdom, Canada Austria, Denmark, Estonia, France, Germany, Ireland, Latvia, Lithuania, Netherlands, Poland, Portugal, Spain, Sweden, Switzerland, Australia, Czech Republic, Finland, Italy, Norway, Slovakia, Slovenia, United Kingdom
Message Volume Low to moderate Moderate High Moderate (for one-way notifications)
Two-Way Communication Supported Supported Supported Not Supported (one-way only)
Brand Visibility Low Moderate (localized presence) High High (direct brand recognition)
Use Case Examples Customer support, notifications Local business communications, marketing & promotions High-volume campaigns, 2FA Brand visibility, one-way notifications
Compliance Requirements SMS verification, opt-out support Campaign registration, opt-out support Carrier approval, opt-in proof Varies by country (e.g., France restricts marketing messages)
Format 1-800-XXX-XXXX XXX-XXX-XXXX 5-6 digits Up to 11 characters (letters/numbers)
Example 1-800-555-1234 212-555-6789 12345 MYBRAND123

To send messages across multiple countries, customers must request different numbers based on the number types supported in each destination.

Next steps

Get started with sending SMS

See the following articles for more information: