This document answers common questions about using Alibaba Cloud Voice Service in common mode or dedicated mode. It also provides recommended actions.
1. Core Concepts
1.1 What is common mode?
Common mode is a service model provided by Alibaba Cloud that allows enterprises to quickly use voice call and Captcha services. It has the following features:
No number purchase required: Enterprises do not need to apply for phone numbers separately.
Fast activation: You can start using the service after your enterprise qualification and script are approved.
Smart scheduling: The system automatically selects numbers from a shared number pool to improve reach rates.
Flexible usage: You can apply for text-to-speech templates or upload audio files.
In common mode, Voice Service provides landline numbers from major carriers and cities across China. When you send a voice call or Captcha, the system schedules an outbound number based on predefined logic.
1.2 Which services does common mode support?
Common mode supports only the following scenarios:
voice call
Voice Captcha
Note: For other scenarios, such as intelligent voice bots or Intelligent Speech Interaction, you must apply for dedicated enterprise numbers and use dedicated mode.
1.3 How does common mode differ from dedicated mode?
Comparison item | Common mode | Dedicated mode |
Applicable scenarios | Supports only voice call and Captcha. Does not support intelligent voice bots or Intelligent Speech Interaction. For more information, see Scenarios. | Supports common scenarios in most cases. Note Available scenarios depend on your qualifications and other conditions. |
Activation requirements | No number application is required. This mode uses random numbers from the shared number pool for outbound calls. | You must apply for real phone numbers and use them for outbound calls. You can bind multiple real numbers to one service instance. When you make an outbound call through the service instance, it schedules one of the bound real numbers for the call. |
Outbound Number Concurrency | Both the shared number pool and numbers purchased in dedicated mode have a maximum concurrent number. If you exceed this limit, calls will fail. You must make calls within the specified concurrency limits. Concurrent number: The maximum number of simultaneous outbound calls allowed for a single outbound number. | |
The concurrency of the shared number pool depends on the pool's available capacity at the time of the call. When the pool is busy, outbound calls do not queue—if you exceed the maximum concurrent calls allowed for a single number in the pool, the excess calls will fail. We recommend that you make calls within the specified concurrency limits. | For mobile numbers in dedicated mode, the maximum concurrent number is 3. For landline numbers, it is 15. The concurrent number is set by the carrier. Settings may vary across carriers. You can check the actual value on the Real Number Management page in the console. | |
Usage methods | You can use voice calls or voice verification codes in the following ways: API operations only. | You can use voice calls or voice Captchas in the following ways:
|
Unregister | No number unregistration is required. | If you no longer need a number, unregister it promptly on the Voice Service console page. Note You must wait at least three months after activation before you can unregister a real number. |
Costs | Common mode supports pay-as-you-go and plan packages. For more information, see Pricing for China Voice Service. | Dedicated mode incurs an additional monthly number rental fee. For more information, see Pricing for China Voice Service. |
Term definition: Concurrent number is the maximum number of simultaneous outbound calls allowed for a single outbound number.
2. Usage Guide
How do I use common mode?
When you manage enterprise qualifications, select Common Mode as the number mode.
When you upload audio files, select Common Mode Outbound as the outbound number type.
When you initiate an outbound call, call the SingleCallByVoice — Send voice call using an audio file or SingleCallByTts — Send Captcha or voice call using text-to-speech API operation. Do not specify a caller number. Instead, you must use a template ID that is configured for common mode.
For more information, see Use voice call or Captcha through APIs.
3. FAQ
Can I use common mode plan packages and dedicated number notification plan packages interchangeably?
No. Common mode plan packages and dedicated number plan packages cannot be used interchangeably.
Plan package (dedicated mode): Applies only to dedicated numbers purchased on the page in the Voice Service console.
Plan package (common mode): Applies to users who have not purchased dedicated numbers and instead use the common numbers provided by the platform.
How does the displayed caller ID differ between common mode and dedicated mode? Can I specify the caller ID?
Common mode:
Outbound numbers are landline numbers randomly selected from the shared number pool.
You cannot specify the caller ID.
Call-back is not supported.
Dedicated mode:
The caller ID matches the number you applied for.
When you call the Send voice call or Send Captcha API operation:
If you pass an approved real number to the
CalledShowNumberparameter, the caller ID will be that real number.If you pass a service instance to the
CalledShowNumberparameter, the service instance schedules a bound real number for the outbound call. The caller ID will then be that real number.
How do I buy numbers for common mode in Voice Service?
You do not need to apply for numbers in common mode. After you obtain common mode qualifications and templates, you can begin making outbound calls.
How many numbers does common mode provide for outbound calls?
The shared number pool provides caller numbers based on the number of calls you need to place.
When calling an API with a dedicated number, does the caller ID change?
If you use a dedicated number, the caller ID does not change.
If you use a number from the shared number pool, the outbound number is random. The caller ID shown to recipients varies.
Can previously activated dedicated numbers still be used?
Log on to the Voice Service console. Then check the status of your numbers on the Real Number Management page.
If the status is Normal, you can test whether outbound calls work.
If the status is Inactive, Abnormal, or Revoking, the number has been deactivated or is otherwise unavailable. You should unregister it as soon as possible.
After applying for a dedicated number, can I still use common mode?
Yes, you can. After you apply for a dedicated number, you can continue using the shared number pool. Common mode and dedicated mode operate independently and do not interfere with each other.
Plan packages for dedicated mode and common mode cannot be shared.
You must apply for voice templates separately for dedicated mode and common mode.
I cannot apply for a dedicated number. Why?
Dedicated numbers are limited in supply. If you cannot apply for a number, it means that no numbers are currently available for purchase. If your approved qualifications are for common mode, you can use common mode instead. You do not need to activate numbers to start using it.
A common mode number is blocked. How do I resolve this?
Caller numbers in the shared number pool are used by many customers. Some numbers may be flagged as spam by third-party apps or recipients, which causes call blocking. Related symptoms include: calls going unanswered with no reason returned by the carrier, a low call answer rate, or multiple simultaneous outbound calls all failing.
Recommended action:
Alibaba Cloud cannot intervene in any way.
To reduce the risk of call blocking, you can purchase dedicated numbers and use dedicated mode.
How do I prevent number blocking and improve the Voice Service answer rate?
To reduce the risk of number blocking and improve your call answer rate, we recommend the following practices:
Use dedicated mode with real numbers: Dedicated mode uses fixed real phone numbers for outbound calls. Real numbers are less likely to be flagged as spam compared to shared pool numbers.
Use compliant call scripts: Ensure your call content complies with carrier regulations and does not trigger spam detection.
Control your calling frequency: Avoid calling the same number too frequently. We recommend no more than 1 call per minute and no more than 5 calls per hour to a single called number.
Avoid restricted calling hours: Do not make outbound calls between 21:00 and 09:00 or between 12:00 and 14:00.
What are the call throttling limits and allowlist rules for Voice Service?
Call throttling limits
Call throttling limits apply per called number under the same qualification and number purpose. Each called number is tracked independently—the limit is not a combined total across all called numbers. For voice call and Voice Captcha, the throttling rules for the same called number are: 1 call per minute, 5 calls per hour, and 20 calls per 24 hours.
Allowlist rules
The allowlist feature is available only in dedicated mode for service instances that have real phone numbers bound. Called numbers added to the allowlist are exempt from call throttling limits.
Common mode (also known as no-number mode) does not support allowlist configuration.
Can common mode be upgraded to dedicated mode? Are plan packages interchangeable?
No. Common mode cannot be directly upgraded to dedicated mode, and plan packages for the two modes are not interchangeable.
If you need to make outbound calls using a fixed real phone number, you must apply for a dedicated number separately in the Voice Service console and configure a dedicated mode template.
Pricing differences:
Common mode (also known as no-number mode): No monthly number rental fee. You are billed on a pay-as-you-go basis or can purchase a common mode plan package.
Dedicated mode: Incurs a monthly number rental fee in addition to call usage charges. The monthly rental fee is CNY 35 per number. For more information, see the pricing documentation.