mathematics

INum Initiative

INum Initiative is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand INum Initiative rather than just read about it. In short: The iNum (international number) initiative was a project by Voxbone to create a global dial code for Voice over IP communications. Voxbone is a Belgian company specializing in wholesale telephone numbers for VoIP applications.

Key takeaways

INum Initiative belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect INum Initiative to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of INum Initiative from memory before moving on to harder problems.

Reference excerpt

The iNum (international number) initiative was a project by Voxbone to create a global dial code for Voice over IP communications. Voxbone is a Belgian company specializing in wholesale telephone numbers for VoIP applications. The International Telecommunication Union (ITU) allocated a portion of the non-geographic "country code" +883 to this initiative. Specifically, iNums were telephone numbers in the format +883 5100 xxxxxxxx. The system started operating in November 2008. Many providers offered iNum numbers and calls between them at no cost to their customers, but some charged for the service. Due to slow adoption, cost and compatibility issues, and the eventual lack of interest by Voxbone in maintaining the system, it was decommissioned in June 2020.

Technical standards The iNum networking was based on SIP standards and supported voice, video and SMS. Transcoding was available between G.711 and G.729. Video codecs supported were H.263+ and H.264, but theoretically any codec, including Skype's SILK and G.722, for high-definition voice, could be supported as long as the originating and terminating networks both supported it and transcoding was not required.

Participating organizations and access Voxbone provided free telephone number ranges to IP communications service providers, enterprises, NGOs and universities. Approximately 400 organizations were allocated iNum ranges. Popular VoIP providers offering iNum numbers to the general public included Callcentric, ippi, Localphone and VoIP.ms. While +883 is a valid ITU dial code, not all telephone carriers could route the calls correctly. Skype, Belgacom, British Telecom, Colt, Google Voice, KPN, Orange Switzerland, Sprint USA and Verizon Europe were among the large communications companies that routed voice calls to iNum. SMS to iNum was supported by several agreements with international messaging providers. It was also possible to call iNums through access numbers in many countries and cities, so callers could make local calls to iNum when their local carrier did not support routing. The caller would dial the local access number, then after the automated greeting dial the desired iNum. In addition, iNums could be called through VoIP methods such as ENUM (RIPE e164.arpa) and SIP URI (format 8835100xxxxxxxx@sip.inum.net). Country code +888 was allocated for the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) international disaster response and implemented using the iNum platform.

Cost Voxbone offered free SIP termination to all service providers who offered it to their customers at or below the cost of a local call, leading many providers to offer the service at no cost. For example, Callcentric and ippi offered free iNum numbers and calls to any customer, and VoIP.ms offered them at no additional cost to existing customers. Localphone initially offered free iNum numbers, later charging $0.25 per month from July 2018, but calls were always free. Google Voice began supporting calls to iNum in 2012, initially at no cost, but in 2013 it set a rate of $0.03 per minute.

Later developments and decommissioning After initial interest by many VoIP providers, adoption was slow. Most providers did not support iNum calls at all, and some of those that supported such calls charged for them, undermining the value of the project. In later years the initiative began showing signs of abandonment. The iNum blog had no new posts after April 2015, and in July 2019 the whole iNum website was redirected to the Voxbone website, which no longer mentioned the project. Callcentric, one of the initial supporters, reluctantly discontinued its iNum service in November 2019 due to incompatibility after an equipment upgrade. In February 2020, Voxbone announced that it would decommission the system later that year, and the decommissioning was completed in June 2020. Calls to iNum may still connect internally within the same provider, but not between providers.

See also International Networks (country code)

References

External links iNum Initiative Website via the Internet Archive "The Internet Gets its Own Country Code" "Creating a Country Called VoIP"

Worked examples

Example 1 — a first encounter with INum Initiative

Start with the simplest possible case. Write down what INum Initiative claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to INum Initiative before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about INum Initiative ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of INum Initiative

In research: INum Initiative appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses INum Initiative in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: INum Initiative is common in secondary-school and first-year university syllabi. It links to neighbouring topics Internet Protocol, Telephone numbers, so understanding it makes those chapters shorter.
In everyday life: Look for INum Initiative outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study INum Initiative in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what INum Initiative means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain INum Initiative out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is INum Initiative in simple terms?

Why does INum Initiative matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study INum Initiative?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on INum Initiative.