Understanding Phone Numbers in Turkey

Quick Reference Guide

• Country: Turkey
• Country Code: +90
• International Prefix: 00
• National Prefix: 0
• Regulatory Authority: Information and Communication Technologies Authority (BTK)

Overview

Discover the intricacies of Turkey's telephone numbering plan with this comprehensive guide. Whether you're a telecom professional, developer, or system administrator, understanding Turkey's phone number formats, dialing procedures, and regulatory considerations is essential for effective communication.

Number Structure

General Number Structure

Turkey's phone numbers adhere to the ITU-T E.164 standard, maintaining a maximum length of 15 digits, including the country code. The structure is as follows:

• Country Code: +90
• Area Code: 3 digits (for geographic numbers)
• Subscriber Number: 7 digits (for both geographic and mobile numbers)

Number Formats by Type

Type	Format	Example	Description
Geographic Numbers	+90 (XXX) XXX XXXX	+90 212 345 6789	Standard format for landlines, 3-digit area code + 7-digit subscriber number.
Mobile Numbers	+90 (5XX) XXX XXXX	+90 532 123 4567	Mobile numbers start with 5XX, followed by a 7-digit subscriber number.
Toll-Free Numbers	+90 800 XXX XXXX	+90 800 123 4567	Toll-free numbers start with 800.
Premium Rate	+90 900 XXXX XXXX	+90 900 123 4567	Premium rate numbers start with 900.
Call Center Numbers	+90 444 XX XX	+90 444 12 34	Call center numbers start with 444 and are dialed without an area code.

Regular Expressions for Validation

• Geographic Numbers: ^( +90|0)([2-3]\d{2})(\d{7})$
• Mobile Numbers: ^( +90|0)(5\d{2})(\d{7})$
• Toll-Free Numbers: ^( +90|0)800(\d{7})$
• Premium Rate Numbers: ^( +90|0)900(\d{7})$
• Call Center Numbers: ^( +90|0)444(\d{2})(\d{2})$

Dialing Procedures

Domestic Calls

• Landline to Landline: Dial 0 + Area Code + Subscriber Number.
  Example: 0 212 345 6789
• Landline to Mobile: Dial 0 + Mobile Prefix + Subscriber Number.
  Example: 0 532 123 4567
• Mobile to Mobile: Dial 0 + Mobile Prefix + Subscriber Number.
  Example: 0 532 123 4567

International Calls

• Outgoing: Dial 00 + Country Code + Area Code + Subscriber Number.
  Example to the US: 00 1 212 555 1234
• Incoming: Dial +90 + Area Code + Subscriber Number (omit the leading 0).
  Example: +90 212 345 6789

Number Portability

Turkey supports number portability for both mobile and fixed-line numbers, allowing users to retain their numbers when changing service providers. This process is overseen by the Information and Communication Technologies Authority (BTK).

Major Telecom Operators and Number Ranges

Operator	Mobile Prefixes	Geographic Prefixes
Turkcell	530-539, 561	N/A
Vodafone	540-549	N/A
Türk Telekom	500-509, 550-559	N/A

ITU-T Standards Compliance

Turkey complies with several ITU-T recommendations:

• E.164: International public telecommunication numbering plan.
• E.123: Notation for national and international telephone numbers.

Number Allocation and Management

The Information and Communication Technologies Authority (BTK) is responsible for the allocation and management of telephone numbers in Turkey, ensuring efficient use and availability for future demand.

Technical Restrictions and Special Cases

• Golden Numbers: These are highly desirable numbers often sold at a premium, though not explicitly regulated.
• Number Blocking: Users can request the blocking of certain number types, such as premium-rate services, through their telecom provider.

Technical Considerations for Developers

When integrating Turkish phone numbers into software systems, consider the following:

1. Validation: Utilize the provided regular expressions to validate Turkish phone numbers.
2. Formatting: Ensure numbers are formatted according to ITU-T E.164 standards for international use.
3. Portability: Implement logic to accommodate number portability for accurate call and message routing.
4. Localization: Be mindful of Turkey's national prefixes and formatting rules when displaying numbers to users.