Vietnam Voice Features and Restrictions

International reach:

• Calls from International numbers are supported.

Domestic reach:

• Domestic Vonage numbers must only be used to place calls via Vonage Voice API.
• Domestic calls from non-Vonage numbers are best effort.
• The self-service buying of numbers is not available for Vietnam at this time on Vonage's Customer Dashboard. Customers can still request a new number from Customer Dashboard by filling in and submitting the required information or by contacting their Account Manager to start the order. After the request is reviewed and there is no issue, the new number will be reserved for customer.
• Outbound calls from Toll Free numbers are not supported.

No limitations apart from Local CLI or Invalid CLIs as explained in In-Country, Local, or No-CLI Calls Rejected

• Advertising calls must be immediately terminated after the user sends an opt-out request
• Every advertiser shall not be allowed to make more than 1 advertising call to a single phone number within 24-hours period, unless the user agrees otherwise
• Advertising calls can only be made between 08:00 to 17:00 every day.

No other limitations beyond those in our Acceptable Use Policy.

Operator is going to block a caller number if:

• Making calls to many subs over 30 calls/hr 
• Time between calls is always below 30 seconds.
• Over 90% callee is not related with caller 
• Average Call duration is short. (eg, most of the calls is shorter than 30 seconds)
• The number could not be called back.
• The number have been reported as spam source from many end users.

No other limitations beyond those in our Acceptable Use Policy.