1. Definition of SIP, SIM and virtual numbers

Every telco owns a specific collection of numbers; for example: Viettel has 098x.xxx.xxx, Mobifone has 090x.xxx.xxx,etc.

Each number ( eg: 0986.123.456) can be registered to a different type of service supplied by their telco:

Normal phone number: The most popular type that enables calling, texting, 3G/4G with a SIM card.

Data number: Also comes in a SIM card but only made for 3G/4G hotspot devices like DCom, Huawei E5573, etc. This type of number can’t make or take phone calls and can only be used for SMS and 3G/4G.

SIP number or SIP Trunk: A newly introduced service that looks like a normal number ( eg: 0986.123.456). However, it doesn’t come with a physical SIM, that's why it can also be called a “virtual number”. A SIP number cannot use data nor send SMS ( some telcos are starting their tests and trials on allowing SMS for SIP, but it’s only in development). This number also can’t register any VAS services like: lobby music, missed calls notifications, etc.

2. How to use a SIP number

Because a SIP number doesn’t have a SIM card that come with it, it has to be registered to a software capable of supporting SIP; or “connect” to a calling service software, call center program that support SIP.

Stringee supports calling and answering services and supplies a contact center program that follows SIP standards. For those reasons, Stringee’s products can be connected to SIP numbers from any telco.

A SIP number supports an unlimited number of calls at the same time. Different from a normal number, when you are in an existing call, you can’t take another call. This is why SIP number is widely used as a contact center’s number or hotline.

3. Converting a SIM number to SIP and vice versa.

At the core, SIP or SIM numbers are both phone numbers in a telco’s collection, so when you look at the number, you wouldn’t know what type of number it is. The only difference is the type of service that is registered to that number.

Because of their indifference, a normal number (SIM) can totally be converted into a SIP and vice versa. To make the conversion, the user has to contact the telco they’re using by going to a local store, bringing their government ID and business registration certificate ( if they’re a business).

You can also register a new number as a SIP right from the start.

4. Which telco has SIP services?

At the moment, every telco in Vietnam has SIP services

FPT, CMC: every number is a SIP number

VNPT: https://vnpt.com.vn/web/doanh-nghiep/-/sip-trunking-co-inh

Viettel, VinaPhone, Vietnamobile: these telcos have SIP number but they haven’t started selling publicly, Stringee can help you with acquiring numbers from said telcos

MobiFone: http://proconnect.mobifone.vn

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