How DNC file layout formats tell VICIdial where to find numbers

Every international DNC list file you upload to VICIdial can arrive in a different format. Some files have phone numbers in the first column. Others bury them deeper in a delimited row, or use a fixed-width layout. Without knowing the file's structure, the processing script cannot reliably extract the right field. That is what the DNC file layout setting solves: it tells the script what kind of file it is dealing with and exactly where to look for the phone number in each row.

What the file layout field controls

When you configure an uploaded DNC file before pressing START FILE, you pick three things: a country code, a file action, and a file layout. The file layout is the format descriptor. It maps to a set of parsing instructions that the automated background script uses when reading through the file line by line. Pick the wrong layout and the script may extract the wrong column, skip all rows, or load incorrect data into the suppression table. Pick the right one and every phone number lands correctly in the country's Internal DNC table.

flowchart TD
  A[DNC file uploaded] --> B[Admin selects file layout from dropdown]
  B --> C[Layout maps to DNC_IMPORT_FORMATS entry]
  C --> D[START FILE pressed]
  D --> E[Background script reads format definition]
  E --> F{Format type?}
  F -->|Column-based| G[Extract column N from each row]
  F -->|Fixed-width| H[Extract characters at position X to Y]
  F -->|Other defined format| I[Apply custom parsing rule]
  G --> J[Phone numbers inserted into country DNC table]
  H --> J
  I --> J

Where the format definitions come from

The options available in the file layout drop-down menu are not hard-coded into VICIdial's interface. They come from a settings container called DNC_IMPORT_FORMATS. This container holds the format definitions, and you can add or modify entries there when you need to support a file type that is not already listed. If a provider sends you files in a non-standard layout and the format does not appear in the drop-down, the correct fix is to define it in DNC_IMPORT_FORMATS first, then return to the loader and process the file.

What to do when your format is not listed

If the drop-down does not include a layout that matches your file, do not guess the closest-sounding option. Processing a file with the wrong layout can silently load wrong data into the suppression table, or fail to load anything at all. Open the DNC_IMPORT_FORMATS settings container, review the existing format definitions to understand their structure, and add a new entry describing where the phone number field sits in your file type. Once saved, the new format appears in the drop-down and you can proceed with loading the file correctly.

Why the format matters for compliance

A DNC suppression table is only as reliable as the data that went into it. If the file layout was set incorrectly during a previous load, numbers that should be suppressed may never have made it into the table — meaning the Lead loader has been passing them through to your Campaign unchecked. After correcting a format mismatch, it is worth reloading the file with the right layout (using PURGE if the previous load populated bad data) to bring the table to a known-good state.

A practical checklist before you process any file

• Open a sample of the file in a text editor and identify which column or character position holds the phone number.
• Open DNC_IMPORT_FORMATS and find a layout entry that matches that structure.
• If no matching entry exists, create one before returning to the loader page.
• Select the correct layout in the drop-down before pressing START FILE.
• After the file finishes processing, verify a sample of numbers from the file are now present in the country's suppression table.

For the full loading walkthrough including country code and file action selection, see how to upload and load a country DNC list in bulk. For the broader picture of VICIdial's batch admin tooling, read our VICIdial admin bulk tools guide.

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