Area Code 85 – Agusan del Sur/Agusan del Norte

Geographic Coverage and Administrative Jurisdiction

The country calling code +63, assigned to the Philippines under ITU-T E.164, uses the National Destination Code (NDC) 85 to designate a geographic numbering area covering the provinces of Agusan del Sur and Agusan del Norte, both located in the Caraga administrative region on the island of Mindanao. This NDC serves the fixed-line (PSTN) infrastructure within these provinces, including the chartered cities of Butuan (the regional center) and Cabadbaran, as well as the municipalities of Prosperidad, Bayugan, San Francisco, and other population centers. The geographic allocation means that the prefix is tied to a physical exchange area, and calls are routed based on the subscriber's location.

Dialing Formats and Number Structure

Within the Philippines, calls to a subscriber in the Agusan area require the trunk prefix 0 followed by the NDC 85 and the subscriber's 7-digit local number. For example, a local call from Manila to a fixed line in Butuan would be dialed as 0 85 XXX XXXX. From outside the Philippines, callers must use the international access prefix (e.g., 00 or +) followed by the country code 63, the NDC 85 (without the leading trunk zero), and the 7-digit local number. Thus, an international caller would dial +63 85 XXX XXXX. This format is essential for proper call routing through international gateways.

Overlays and Numbering Plan Considerations

As of the current Philippine National Numbering Plan, there are no overlay codes in the Agusan region; the NDC 85 is exclusively assigned to the geographic area. However, the National Telecommunications Commission (NTC) has implemented measures to ensure numbering resource efficiency, and future overlays or migrations may occur. Subscribers in this area may have access to VoIP and mobile services, but fixed-line numbers under 85 remain geographically tied. For callers, it is important to note that when dialing from a mobile phone within the Philippines, the trunk prefix 0 is still required, but the call may be treated as a domestic long-distance call, potentially incurring higher charges.

Caller Instructions and Practical Guidance

For local callers within the Agusan provinces, local calls may be dialed using the 7-digit local number alone if the caller and callee share the same exchange area. However, for calls from other regions in the Philippines, the full domestic format 0 85 XXX XXXX is mandatory. International callers should always use the plus sign (+) or the appropriate international prefix, followed by 63 85 XXX XXXX. It is advisable to confirm the exact local number length with the subscriber, as some rural exchanges may still use older 6-digit numbers; in such cases, the international format would be +63 85 XXX XXX. Always verify the number before dialing, especially when using VoIP services, which may require different dialing rules.