Until a few years ago, TDM networks were the default choice for Air Traffic Management (ATM) voice communications, and for ATM data serial connectivity was used. Today, these legacy networks are being phased out, and a migration to Voice over Internet Protocol (VoIP) and converged IP networks is in process. Organizations such as the International Civil Aviation Organization (ICAO), the European Organization for Civil Aviation Equipment (EUROCAE), Single European SkATM Research (SESAR) project and the NextGen program of the Federal Aviation Administration (FAA) have defined guidelines on how to accomplish the transition to IP-based networks.
Aeronautical voice communications or “Voice ATM” communications include all voice applications used for the purposes of Air Traffic Management (air-ground communications, co-ordination and transfer, emergency, Search and Rescue, flow management, capacity planning), ATM voice covers intra- and inter- center (all types of ATSUs: ACC, APP, TWR, MIL, NMOC) communications and also ensures the connectivity between the centers and the ground radio based stations on the ground leg of the Air-Ground communications between controllers and pilots. Thus, it is a very unique and “critical” type of communications and as such it has to operate according to very high standards of reliability, robustness and interoperability.
Why Voice ATM is Unique
Voice ATM cannot be handled the same way as non-aviation use communications. We have all heard that in commercial wired and wireless communications there are several industry accepted voice compression protocols such as algorithms such as G.711, G.722, G.729 etc.
In addition, those of us that have worked in the radio communications industry for some time have become accustomed to the implementation of various radio over IP modes such as DMR, IDAS, MotoTRBO, Nexedge, P25 and Tetra.
These may work well for ground-only communications but when it comes to ground-air communications they don’t fulfill the need. One of the main reasons for this is that regular two-way radio RoIP or VoIP don’t consider is interoperability. ED-137 compliant systems must be interoperable regardless of the manufacturer or the type of equipment. Thus, an ED-137B compliant voice switch (VCS) from manufacturer A has to be compliant with an ED-137B VHF radio from manufacturer B. There are several other aspects that ED-137 considers as well such as:
- Quality of Service (QoS)
- Supervision
- Security
- Allowing aviation specific modes such as CLIMAX (requires Time Stamping)
- PTT (Push-to-Talk)
How Morcom Can Help You
Morcom distributes the CRU995 Gateway. This device has multiple applications: It can be used to connect legacy systems to new ED-137 compliant IP systems. Like for example, a legacy VCS that uses E&M type connections can be connected to ED-137 IP-type radio transmitters and receivers. And vice versa, an IP-type VCS can be connected to legacy analog radios. The CRU995 is an excellent tool to help you migrate to a fully digital VoIP system in a gradual fashion without having to discard fully functional equipment.
What follows is a detailed explanation on how the CRU995 can help you fulfill specific applications:
Case 1 - Using Legacy VCS and Legacy VHF Radios
Case 2 - Connection of a Legacy VCS to ED-137 VHF Radios
Case 3 - Connection of a Digital VCS to Legacy Radios
Case 4 - Full ED-137 Digital Network
For more information call us at 1-800-683-4101 or contact us through the request form.
