What is the country code for Guam (GU)?

The country code for Guam (GU) is +1, and the area code is 671.

How are mobile numbers structured in Guam?

Mobile numbers in Guam follow the format +1 671 NXX XXXX, where 'NXX' is the exchange code (N is any digit from 2-9, and X is any digit from 0-9), followed by a 4-digit subscriber number.

What are the dialing procedures for international calls to Guam?

To make an international call to Guam, dial your country's international prefix (e.g., 011 from the U.S.), followed by Guam's country code +1, the area code 671, and the 7-digit subscriber number.

Is number portability supported in Guam?

Yes, Guam supports number portability, allowing subscribers to retain their phone numbers when switching between service providers for both mobile and landline numbers.

Which major telecom operators provide services in Guam, and what are their number ranges?

The major telecom operators in Guam are Guam Telephone Authority (GTA) with number ranges 671-300 to 671-999, Docomo Pacific with number ranges 671-988 to 671-999, and IT&E Guam with number ranges 671-777 to 671-888.

What is the country code for Guam?

The country code for Guam is +1 671.

How do I dial a landline number in Guam from the United States?

To dial a landline number in Guam from the United States, dial 1 + 671 + the 7-digit subscriber number.

What is the international prefix used in Guam for outgoing calls?

The international prefix used in Guam for outgoing calls is 011.

Can I keep my phone number if I switch providers in Guam?

Yes, Guam supports number portability, allowing you to keep your number when switching providers.

What is the format for a mobile number in Guam?

The format for a mobile number in Guam is +1 671 NXX XXXX, where NXX is the exchange code.

Are there any toll-free numbers in Guam?

Yes, toll-free numbers in Guam follow the format +1 800 XXX XXXX.

How do I validate a Guam landline or mobile number using regex?

You can validate a Guam landline or mobile number using the regex: ^\+1\s671\s[2-9][0-9]{2}\s[0-9]{4}$.

Who regulates phone numbers in Guam?

The Federal Communications Commission (FCC) regulates phone numbers in Guam.

What is the national prefix for dialing within Guam?

The national prefix for dialing within Guam is 1.

What area code do all phone numbers in Guam use?

All phone numbers in Guam use the area code 671.

How are premium rate numbers formatted in Guam?

Premium rate numbers in Guam are formatted as +1 900 XXX XXXX.

Which telecom operators are major providers in Guam?

Major telecom operators in Guam include Guam Telephone Authority (GTA), Docomo Pacific, and IT&E Guam.

What is the subscriber number length for phone numbers in Guam?

The subscriber number length for phone numbers in Guam is 7 digits.

How do I dial an international call from Guam?

To dial an international call from Guam, dial 011 + Country Code + Area Code + Subscriber Number.

Is number blocking available in Guam?

Yes, number blocking is available upon request from telecom operators in Guam.

Does Guam follow the North American Numbering Plan (NANP)?

Yes, Guam follows the North American Numbering Plan (NANP).

What are the number ranges for Docomo Pacific in Guam?

Docomo Pacific in Guam uses the number ranges 671-988 to 671-999.

What ITU-T recommendations does Guam adhere to?

Guam adheres to ITU-T recommendations including E.164 and Q.731.

What should developers consider when integrating Guam's phone numbers into software?

Developers should consider validation using regex, maintaining consistent international formats, and implementing logic for number portability.

Understanding Phone Numbers in Guam

Quick Reference Guide

Country: Guam
Country Code: +1 671
International Prefix: 011
National Prefix: 1
Regulatory Body: Federal Communications Commission (FCC)

Overview

Guam, a U.S. territory, follows the North American Numbering Plan (NANP). This guide provides a detailed look at Guam's phone number formats, dialing procedures, and the regulatory framework governing telecommunications.

Number Structure

General Number Structure

Country Code: +1
Area Code: 671
Subscriber Number Length: 7 digits

Detailed Number Formats

Type	Format	Example
Landline	`+1 671 NXX XXXX`	+1 671 472 1234
Mobile	`+1 671 NXX XXXX`	+1 671 988 5678
Toll-Free	`+1 800 XXX XXXX`	+1 800 234 5678
Premium Rate	`+1 900 XXX XXXX`	+1 900 345 6789

NXX: Represents the exchange code, where N is any digit from 2-9, and X is any digit from 0-9.

Regular Expressions for Validation

Landline & Mobile:
```
^\+1\s671\s[2-9][0-9]{2}\s[0-9]{4}$
```
Toll-Free:
```
^\+1\s800\s[2-9][0-9]{2}\s[0-9]{4}$
```
Premium Rate:
```
^\+1\s900\s[2-9][0-9]{2}\s[0-9]{4}$
```

Dialing Procedures

Domestic Calls

Landline to Landline: Dial 1 + 671 + 7-digit subscriber number.
Landline to Mobile: Dial 1 + 671 + 7-digit subscriber number.
Mobile to Mobile: Dial 671 + 7-digit subscriber number.

International Calls

Outgoing: Dial 011 + Country Code + Area Code + Subscriber Number.
Incoming: Dial +1 671 + 7-digit subscriber number.

Number Portability

Guam supports number portability, allowing users to keep their numbers when switching providers, applicable to both mobile and landline numbers.

Major Telecom Operators

Operator	Service Type	Number Ranges
Guam Telephone Authority (GTA)	Landline & Mobile	671-300 to 671-999
Docomo Pacific	Mobile	671-988 to 671-999
IT&E Guam	Mobile	671-777 to 671-888

ITU-T Recommendations

Guam adheres to ITU-T recommendations under the NANP, including:

E.164: International public telecommunication numbering plan.
Q.731: ISDN user-network interface layer 3.

Number Allocation and Management

The FCC manages phone number allocation in Guam, ensuring compliance with NANP standards.

Technical Restrictions and Special Cases

Golden Numbers: No specific regulations in Guam.
Number Blocking: Available upon request from telecom operators.

Technical Considerations for Developers

When integrating Guam's phone numbers into software, consider:

Validation: Use provided regex for number validation.
Formatting: Maintain consistent international formats.
Portability: Implement logic for number portability.

For the latest on Guam's telecom regulations, visit the FCC's official website.

Recent Changes to Numbering Plan

There have been no recent changes to Guam's numbering plan since its inclusion in the NANP in 1997.

Conclusion

Understanding Guam's phone number system is crucial for telecom professionals and businesses. By following this guide, you can ensure compliance with regulations and enhance your telecommunications infrastructure.

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