The official PDF is required by:

The NATO Standardization Office (NSO) Database: The primary source for official, up-to-date documents. stanag 4157 pdf

I notice you're looking for (likely a NATO standard for vehicle intercom/radio systems, part of the "Digital Euro-ISDN" or military communications family). The official PDF is required by: The NATO

Stanag 4157 Pdf <Mobile TRUSTED>

The official PDF is required by:

The NATO Standardization Office (NSO) Database: The primary source for official, up-to-date documents.

I notice you're looking for (likely a NATO standard for vehicle intercom/radio systems, part of the "Digital Euro-ISDN" or military communications family).