<aside> 🧭

DCID selection priority

1. Exact NPA → 2. LATA-associated NPA → 3. State-associated NPA → 4. Original caller number

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🎯 Purpose

The DCID geographic caller ID selection enhancement improves caller ID selection when the dialed destination's exact area code has no configured number. It uses NPA-NXX, LATA, and State mapping data to find the nearest geographically relevant caller ID while preserving the existing exact-match behavior and final fallback.

🗺️ Selection flow

<aside> 💡

How to read this chart: Follow the No path downward through progressively broader geographic matches. Any Yes path selects a caller ID and ends processing.

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flowchart TD
    A(["Incoming dialed number"]) --> B["Extract NPA + NXX"]
    B --> C{"1. Exact NPA has an available DCID number?"}

    C -- "YES" --> X1["Select a random number from the exact NPA"]
    C -- "NO" --> D["Resolve LATA from the NPA-NXX mapping"]

    D --> E["Retrieve NPAs associated with the LATA"]
    E --> F{"2. Any LATA-associated NPA has an available number?"}
    F -- "YES" --> X2["Select a random number from the first matching LATA NPA"]
    F -- "NO" --> G["Resolve State from the NPA-NXX mapping"]

    G --> H["Retrieve NPAs associated with the State"]
    H --> I{"3. Any State-associated NPA has an available number?"}
    I -- "YES" --> X3["Select a random number from the first matching State NPA"]
    I -- "NO" --> X4["4. Use the original caller number"]

    X1 --> Z(["Selection complete"])
    X2 --> Z
    X3 --> Z
    X4 --> Z

    classDef input fill:#E7F3FF,stroke:#2383E2,color:#1F2937,stroke-width:2px;
    classDef decision fill:#FFF3BF,stroke:#CB912F,color:#1F2937,stroke-width:2px;
    classDef match fill:#DBEDDB,stroke:#448361,color:#1F2937,stroke-width:2px;
    classDef fallback fill:#FDECC8,stroke:#D9730D,color:#1F2937,stroke-width:2px;
    classDef done fill:#E8DEEE,stroke:#9065B0,color:#1F2937,stroke-width:2px;

    class A,B,D,E,G,H input;
    class C,F,I decision;
    class X1,X2,X3 match;
    class X4 fallback;
    class Z done;

<aside> 1️⃣

Exact NPA

Best match

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<aside> 2️⃣

LATA

Regional fallback

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<aside> 3️⃣

State

Broader fallback

</aside>

<aside> 4️⃣

Original caller

Final fallback

</aside>

⚙️ Implemented matching stages

1️⃣ Exact NPA match

<aside> ✅

Highest priority: If an exact NPA match exists, select it and stop. No broader geographic lookup is performed.

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1. Extract the NPA from the dialed number.
2. Search the configured DCID list for numbers associated with that NPA.
3. If one or more numbers are available, randomly select one.
4. End processing.

Example

2️⃣ LATA-based NPA match

<aside> 🌐

Regional fallback: Used only when the exact NPA has no available configured number.

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