The structure of a mobile number varies by country, but here are some general components:
1. Country Code: This is a one- to three-digit code that represents the country. For example, the country code for the United States is +1, for India it is +91.
2. National Destination Code (NDC) / Area Code: This is a code that represents a specific region or city within the country. This can vary in length.
3. Subscriber Number: This is the unique number assigned to the individual subscriber. Its length can vary depending on the country and the length of the NDC.
For example, a mobile number in the United States might look like this:
+1-XXX-XXX-XXXX
Where `+1` is the country code, and `XXX-XXX-XXXX` is the combination of the area code and the subscriber number.
In India, a typical mobile number might look like this:
+91-XXXXX-XXXXX
Where `+91` is the country code, and `XXXXX-XXXXX` is the subscriber number (often divided into two groups of five digits for easier readability).
In India, the structure of a mobile number is as follows:
1. Country Code: `+91`
2. National Destination Code (NDC) / Mobile Operator Code: The first five digits after the country code, which often indicate the mobile operator and sometimes the region.
3. Subscriber Number: The remaining five digits.
So, a typical Indian mobile number looks like this:
+91-XXXXX-XXXXX
Here, `+91` is the country code, and `XXXXX-XXXXX` represents a 10-digit mobile number divided into two groups for better readability. The first five digits often identify the mobile operator and sometimes the region, while the last five digits are unique to the subscriber.
For the number `1234567890` as an Indian mobile number, it would be structured as follows:
1. Country Code: `+91`
2. National Destination Code (NDC) / Mobile Operator Code: `12345`
3. Subscriber Number: `67890`
So, the complete number would be formatted as:
+91-12345-67890
In India, the assignment of mobile numbers, including the subscriber number, is managed by the Department of Telecommunications (DoT). Here's a general overview of how subscriber numbers are assigned:
1. Block Allocation: The DoT allocates blocks of mobile numbers to mobile operators. Each block starts with a specific series of digits that identify the operator and sometimes the region.
2. Operator Assignment: Within the allocated blocks, the mobile operators then assign individual subscriber numbers to new customers. This assignment is typically sequential within the block.
3. Mobile Number Portability (MNP): Subscribers can retain their mobile numbers when switching from one mobile operator to another, thanks to Mobile Number Portability (MNP). The number remains the same even if the operator code originally indicating the operator changes.
For example, if a mobile operator is allocated the block starting with `12345`, they can assign numbers in this range like `1234500000` to `1234599999`. When a new subscriber joins, they will get the next available number in this block.
This system ensures that each mobile number is unique and can be traced back to the block and operator it was originally assigned to.
The National Destination Code (NDC) in the context of mobile numbering is part of the telephone number that typically identifies the specific region or the mobile network operator within a country. In some countries, it's also known as the area code or the network code. For mobile numbers, it often indicates the mobile service provider and sometimes the region.
In India:
The NDC for mobile numbers usually comprises the first few digits of the 10-digit mobile number, immediately following the country code. It helps route the call to the appropriate mobile network operator.
For example, in a typical Indian mobile number formatted as `+91-XXXXX-YYYYY`:
- `+91` is the country code.
- `XXXXX` is the NDC, which often represents the mobile operator and possibly the region.
- `YYYYY` is the subscriber number, unique to the individual.
Example:
Consider the mobile number `+91-98765-43210`:
- `+91` is the country code.
- `98765` is the NDC, which can be assigned to a specific mobile operator like Vodafone or Airtel and possibly indicate the region of allocation.
- `43210` is the subscriber number.
The NDC ensures that calls are correctly routed to the respective mobile network operator's infrastructure, facilitating efficient call management and connectivity.
When a SIM is ported to another network using Mobile Number Portability (MNP), the handling of the NDC (National Destination Code) and subscriber number changes as follows:
1. Subscriber Number:
The subscriber number (the unique mobile number) remains unchanged. This is the primary goal of porting: to allow users to retain their mobile number regardless of the network provider they switch to.
For example, if your number is 98765XXXXX on Network A and you port to Network B, the number stays the same.
2. NDC (National Destination Code):
The NDC, which is the prefix of your mobile number identifying the original operator and service region (e.g., 98765XXXXX, where "98765" indicates the original operator and circle), does not change even after porting.
Even though the number is now being serviced by a different operator, the original NDC is retained. This is because the number portability system maps the existing number (including its NDC) to the new operator in the backend database used for routing calls and SMS.
Additional Notes:
The porting process ensures that all calls and messages intended for the ported number are correctly routed to the new network, thanks to centralized MNP databases that store the mapping of ported numbers.
While the user experiences no change in their number, the original association of the NDC with the old operator no longer applies, as the number is now serviced by the new operator.
Here are some examples of National Destination Codes (NDCs) for mobile numbers originally assigned to operators in Uttar Pradesh (East and West):
Uttar Pradesh (East):
1. Jio:
7007, 7013, 7991, 7985
2. Airtel:
9935, 8005, 8573, 7004
3. BSNL:
9415, 9450, 8004
4. Vi (Vodafone Idea):
9889, 8574, 7006
Uttar Pradesh (West):
1. Jio:
7017, 7983, 7008
2. Airtel:
9997, 8057, 9719, 7005
3. BSNL:
9412, 9456, 9410
4. Vi (Vodafone Idea):
9837, 9999, 8439, 7019
Notes:
These NDCs were originally allocated to the respective operators in Uttar Pradesh regions.
Due to MNP, a number starting with one of these NDCs may now belong to a different operator.
For accurate operator and circle information, you can use online tools or mobile apps to check the current status of a number.
Let me know if you'd like NDCs for a specific operator or more details!
