text: Appendix D
  JOINT VARIABLE MESSAGE FORMAT
  D-5. Joint variable message format is a modem-based message protocol that provides the most extensive
  digital information exchange between similarly capable platforms and ground-based terminal attack
  controller kits. The variable message format provides an extremely flexible message standard that consists
  of only essential information, allowing shorter messages than USMTF for reduced transmission time and
  network clutter. It is bit-oriented, digital information with variable-length messages. The conveyed data
  requires varying amounts of volume and detail of information, and it can be transmitted over a broad range
  of tactical communications systems. Variable message format uses Link 16 data elements to create variable
  length messages suitable for near-real-time data exchange in a bandwidth constrained combat environment.
  The variable message format is the Army solution to the battlefield digitization interoperability and
  bandwidth problems. Refer to MIL-STD-6017 for a complete listing of all variable message formats.
  UNITED STATES MESSAGE TEXT FORMAT AND VARIABLE MESSAGE FORMAT RECORD
  TEMPLATES
  D-6. Airspace users utilize USMTF and variable message format record templates to record messages and
  reports. Airspace elements routinely use record messages and digitally transmit them via a mission command
  system.
  AIRSPACE CONTROL PECULIARITIES TO BE AWARE OF
  D-7. Requesting airspace requires an understanding of the different airspace coordinating measures, how
  those airspace coordinating measures are communicated (messages) between airspace control nodes, as well
  as the information displays used to integrate airspace use. All users requesting airspace must understand the
  methods used to transmit their airspace use requests. These methods may range from a simple hand-held
  radio during degraded operations, through the most advanced and complex automated systems on the
  battlefield. No matter the situation, effective individual users understand the systems used (such as advanced
  field artillery tactical data system, tactical airspace integration system, theater battle management core
  system) and how system interoperability impacts their airspace use requests.
  AIRSPACE COORDINATING MEASURES PECULIARITIES
  D-8. Airspace coordinating measures are measures employed to facilitate the efficient use of airspace to
  accomplish missions and simultaneously provide safeguards for friendly forces (JP 3-52). While JP 3-52 and
  other doctrinal and joint standards documents define airspace coordinating measures (ACMs), the USMTF
  standard defines the implementation of these ACMs using current digital airspace control systems (such as
  machine-to-machine exchange).
  D-9. The difference or peculiarities between the standards has caused confusion at times. In some cases, the
  name of the ACM differs between joint doctrine and USMTF. In other cases, the nature of the coordinating
  measure changes. In USMTF, a restricted operations zone is a category (type) with many associated
  coordinating measures (usages) one of which is a restricted operations area. The same situation exists for
  special use airspace, which in USMTF is a type, not a usage.
  D-10. Since the language between the various Service command and control systems is USMTF, airspace
  element personnel need to understand how their automation systems use and exchange ACMs. Often airspace
  element personnel have to convert non-digital airspace requests using doctrinal definitions that may not be
  USMTF terms (such as coordinating altitude or restricted operations zone) into the appropriate digital
  USMTF format. In addition, since some digital systems do not process the entire USMTF set of coordinating
  measures, airspace element personnel must understand the peculiarities effects of ACM type, usage, and
  shape selection when translating text into a digital USMTF message to ensure that the ACM yields the desired
  outcome.
  D-11. The shape tool used in the creation of an ACM is a critical aspect on whether the ACM can be processed
  among the systems used to integrate airspace use. For example, the tactical TAIS has eight different shape
  choices while the theater battle management core system has nine shape choices. See Table D-1 on page D-
  3.