5.5 Data Communications
Cospas-Sarsat does not operate any communications networks; it makes use of commercial networks that are available. At the present time, the only networks that are used operationally among the MCCs in the Cospas-Sarsat System are:
· the Internet (File Transfer Protocol over Virtual Private Network – FTP/VPN), as the primary network for communications between MCCs, and
· the Aeronautical Fixed Telecommunications Network (AFTN) [1], used to communicate with some RCCs or SPOCs, and as a backup communications link between MCCs.
E-mail messaging is accepted as a back-up service that may be used; however, it is only to be used when the primary communications services are not available.
[1] The AFTN protocol is described in Annex 10 of the Chicago Convention. (See section 9.2 of this document.) ICAO is currently in the process of upgrading the AFTN for Air Traffic Services (ATS) to the ATS Message Handling System (AMHS or ATSMHS) (also known as Aeronautical Message Handling System). Cospas-Sarsat MCCs will convert to this new system as it becomes available in each country. However, since the AHMS is compatible with the AFTN, this is not expected to cause any significant issues during the conversion.