Calilio is a Voice over Internet Protocol (VoIP) platform that allows you to make and receive calls over the Internet. It offers high-quality voice communication, comparable to or better than traditional landline phone service.

How does Calilio work?

Calilio converts your voice into a digital signal that travels over the internet. You can make a call directly from a computer, a special VoIP phone, or a traditional phone connected to a special adapter.

Does VoIP use a SIM card?

A VoIP phone does not use a SIM card. It uses an internet connection to make and receive calls. VoIP phones can be used on any device with internet access, including a computer, smartphone, or a special VoIP phone.

Why should I use Calilio instead of traditional phone services?

Calilio offers several advantages over traditional phone services, including lower cost, increased mobility, and advanced features like voicemail-to-email, call forwarding, call monitoring, video conferencing, and more. Our cloud phone system support multiple users on a single account, making it ideal for businesses of all sizes. It also offers mobility, allowing employees to make and receive calls from anywhere, thereby improving communication and productivity.

How to buy a virtual phone number on Calilio?

Buying a virtual phone number on Calilio is easy. Simply sign into your account, go to the 'Virtual Number' section, choose the country and area code you want, and select your number. Once you've selected, follow the prompts to complete the purchase. These online phone numbers allows you to make and receive calls from from any device with an internet connection

Guidelines>SMS Guidelines>Vietnam

Guidelines

Vietnam

Locale Summary

Locale name	Vietnam
ISO code The International Organization for Standardization two character representation for the given locale.	VN
Region	Asia
Mobile country code A three digit code associated with the given locale and used in conjunction with a Mobile Network Code to uniquely identify mobile networks.	452
Dialing code The dialing prefix used to establish a call or send an SMS from one locale to the given locale.	+82

Guidelines

Two-way SMS supported Whether Calilio supports two-way SMS in the given locale.	No
Number portability available Whether number portability is available in the given locale.	Yes
Calilio concatenated message support Concatenation refers to the capability of splitting a message that is too long to be sent in one SMS into smaller pieces and then joining the pieces at the receiving end so that the receiver sees the message as one.	Yes* For certain sender ID types this may not be supported. Where messages are split and rejoined may vary based on character encoding
Message length How many characters can be sent given a particular message encoding before the message will be split into concatenated segments.	160 characters
Calilio MMS support Multimedia Messaging Service (MMS) provides a standards-based means to send pictures and video to mobile phones.	Converted to SMS with embedded URL
Sending SMS to landline numbers How Calilio handles an SMS message destined for landline telephone number.	You cannot send SMS to a landline destination number: the Calilio REST API will throw a 400 response with error code 21614, the message will not appear in the logs, and the account will not be charged.
Compliance considerations Calilio strongly encourages customers to review proposed use cases with qualified legal counsel to make sure that they comply with all applicable laws. This table lists some general best practices.	Sender ID Compliance Vietnam mobile operators require pre-registration of Alphanumeric Sender IDs and message templates. Numeric Sender IDs are overwritten with generic Alphanumeric Sender IDs outside Calilio’s platform. Quality is lower and delivery is on a best-effort basis because generic Alphanumeric Sender IDs are likely to be blocked or filtered by mobile operators. Calilio therefore recommends using pre-registered Alphanumeric Sender IDs and message templates only. Sending promotional traffic (non transactional) is not currently supported. The enforcement of complete blocking of unregistered Sender IDs in Vietnam is on August 25, 2025. Calilio highly recommends sending from a registered Alphanumeric Sender ID to avoid having your messages blocked. Please ensure you pass your exact registered Alphanumeric Sender ID in the “From” parameter when you send a message. Keep in mind that registered senders are case-sensitive. Content Compliance Requirements for SMS Delivery to Vietnam Starting August 12, 2024, all SMS messages to Vietnam must include a brand name or application name in the message body. This name should be similar or identical to the alphanumeric SenderID header you use to send the SMS message. For example, an OTP message from Company ABC could appear like this: [Company ABC] Your verification code is 123456. Any SMS message to Vietnam that doesn’t contain a brand name or application name may be undelivered or blocked after the start date. Mobile operators prohibit sending virtual currency-related content. You must have a license from the State Bank of Vietnam to send finance-related content via Sender ID. Delivery reports are SMSC-acknowledgment only and are not guaranteed. Sending firearms, gambling, adult content, money/loan, political, religious, controlled substance, cannabis, and alcohol related content is strictly prohibited. Messages containing URLs, WhatsApp/LINE chat links, and phone numbers in the body are not allowed. Sending marketing and promotional messages between 8PM to 8AM is prohibited. Calilio strongly encourages customers to review proposed use cases with qualified legal counsel to make sure that they comply with all applicable laws. The following are some general best practices: Get opt-in consent from each end user before sending any communication to them, particular for marketing or other non-essential communications. Only communicate during an end user's daytime hours unless it is urgent. SMS campaigns should support HELP/STOP messages, and similar messages, in the end user's local language. Do not contact end users on do-not-call or do-not-disturb registries.

Phone Numbers & Sender ID ( Alphanumeric)

Pre-registration	International Pre-registration	Domestic Pre-registration	Dynamic
Operator network capability Whether mobile operators in the given country support the feature.	Required	Required	Not Supported
Calilio supported Whether Calilio supports the feature for the given country.	Supported	Supported	Not Supported
Sender ID preserved In some countries sender IDs for certain sender types are not preserved and are changed for compliance and/or deliverability reasons. In these countries mobile subscribers will see a different ‘from sender ID’ than the one sent by you.	Yes	Yes	N/A
Provisioning time Provisioning is the process of getting the sender ID approved and registered with mobile networks (depending on country requirements). Provisioning time is how long this process takes in the given country.	5 weeks	5 weeks	N/A
UCS-2 support	Supported	---	---
Use case restrictions	Mobile operators prohibit sending virtual currency-related content. You must have a license from the State Bank of Vietnam to send finance-related content using a Sender ID. Delivery reports are not supported by all mobile networks other than VietnaMobile. Sending adult, gambling, charity or political content is prohibited. Sending promotional traffic (non transactional) is not currently supported.	Mobile operators prohibit sending virtual currency-related content. You must have a license from the State Bank of Vietnam to send finance-related content using a Sender ID. Delivery reports are not supported by all mobile networks other than VietnaMobile. Sending adult, gambling, charity or political content is prohibited. Sending promotional traffic (non transactional) is not currently supported.	Delivery of messages submitted with unregistered Sender IDs is on a best-effort basis and will be overwritten with either a random Numeric or Alphanumeric Sender ID outside the Calilio platform. The enforcement of complete blocking of unregistered Sender IDs in Vietnam is on August 25, 2025. Calilio highly recommends sending from a registered Alphanumeric Sender ID to avoid having your messages blocked. Please ensure you pass your exact registered Alphanumeric Sender ID in the “From” parameter when you send a message. Keep in mind that registered senders are case-sensitive.
Best practices	On receiving your registration request, the Sender ID team will ask you to upload a colored copy of your business registration certificate. This is a legal document issued by the government or a government-related body that legitimizes the formation of a company or corporation. If the Sender ID you requested is different from or is not affiliated with the company requesting the Sender ID, you will need to submit documentation that proves the company is allowed to use the Sender ID’s brand name. For example, Calilio owns the brand ‘Authy’. When Calilio submits a registration request for Authy, it needs to submit a document that proves Calilio owns the rights to use the Authy brand name.	On receiving your registration request, the Sender ID team will ask you to upload a colored copy of your business registration certificate. This is a legal document issued by the government or a government-related body that legitimizes the formation of a company or corporation. If the Sender ID you requested is different from or is not affiliated with the company requesting the Sender ID, you will need to submit documentation that proves the company is allowed to use the Sender ID’s brand name. For example, Calilio owns the brand ‘Authy’. When Calilio submits a registration request for Authy, it needs to submit a document that proves Calilio owns the rights to use the Authy brand name.	N/A

Long codes and short codes

	Long code domestic	Long code international	Short code
Operator network capability Whether mobile operators in the given country support the feature.	Not Supported	Not Supported	Not Supported
Calilio supported Whether Calilio supports the feature for the given country.	Not Supported	Supported	Not Supported
Sender ID preserved In some countries sender IDs for certain sender types are not preserved and are changed for compliance and/or deliverability reasons. In these countries mobile subscribers will see a different ‘from sender ID’ than the one sent by you.	---	No	---

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