The nine lines

The 9-line request is published in allied doctrine, for example US Army Techniques Publication (ATP) 4-02.2, Medical Evacuation. National variants differ in their codes and in wartime and peacetime wording. The record Gridnorth used in testing is an adapted version, not an APP-11 definition.

Line	Content	How the record handles it
1	Location of the pickup site	Must be a valid MGRS grid reference. A missing digit or an unequal easting and northing is flagged.
2	Radio frequency, call sign and suffix	Held as separate fields. A missing or malformed value is flagged.
3	Number of patients by precedence	Only the allowed precedence values can be produced: Urgent, Urgent-Surgical, Priority, Routine, Convenience.
4	Special equipment required	Chosen from the allowed list, such as none, hoist, extraction equipment or ventilator.
5	Number of patients by type	Litter and ambulatory counts, held as numbers.
6	Security of the pickup site	Chosen from the allowed values.
7	Method of marking the pickup site	Chosen from the allowed values.
8	Patient nationality and status	Chosen from the allowed values.
9	Nuclear, biological or chemical contamination, or the terrain description in peacetime	Chosen from the allowed values, or entered as a short description.

A walk-through

This example is illustrative and is not taken from the test set. The operator dictates: "Nine-line. Line one, three eight sierra, november delta, one two three four, five six seven." The record now holds 38S ND 1234 567. Seven digits cannot be split into equal easting and northing, so it is not a valid grid reference.

Gridnorth marks line 1 as unconfirmed and shows the operator what it heard. The other lines pass their checks and wait for confirmation together. The operator re-reads the grid or corrects it. Only then does deterministic code render the message, validate it and encode it for the link. The flagged grid stays out of the released message until the operator has confirmed it.

This is the failure that matters most. In our tests, grid references, times and callsigns read out digit by digit were the main source of errors, and the next stage moves their parsing to deterministic code. See what is still open.

What has and has not been shown

For a French-speaking operator the request works the same way, with the accuracy figures on the bilingual page. On a narrow link, encoded messages averaged 19 bytes in testing.

Last reviewed September 29, 2026