normally have exceptions for emergency communications. In accordance with long standing amateur radio tradition, international guidelines and FCC rules section 97.113, hams using the Winlink system are advised that it is not appropriate to use it for business communications. Users The Winlink system is open to properly licensed amateur radio operators. The system primarily serves radio users without normal access to the internet, government and non-government public service organizations, medical and humanitarian non-profits, and emergency communications organizations. Duly authorized MARS operators may utilize the MARS part of the system. As of July 2008, there were approximately 12,000 radio users and approximately 100,000 internet correspondents. Monthly traffic volume averages over 100,000 messages. For offshore cruising yachtspeople Winlink is widely used as an alternative, or alongside, Sailmail, which is an HF PACTOR based-email system using marine HF frequencies rather than amateur. As well as email the service uses a system called Saildocs, which allows cruisers to retrieve meteorological, maritime safety and other crucial files over email. Supported radio technologies 802.11 "WiFi" ALE (Automatic Link Establishment) APRS (Automatic Packet Reporting System) AX.25 Packet Radio D-Star PACTOR PACTOR-II PACTOR-III PACTOR-IV WINMOR(Deprecated) ARDOP Vara HF Vara FM TCP/IP (Telnet and other Wireless Technologies) Technical protocols PACTOR-I, WINMOR(deprecated), ARDOP, , HSMM (WiFi), AX.25 packet, D-Star, TCP/IP, and ALE are non-proprietary protocols used in various RF applications to access the Winlink network systems. Later versions of PACTOR are proprietary and supported only by commercially available modems from Special Communications Systems GmbH. In amateur radio service, AirMail, Winlink Express, and other email client programs used by the Winlink system, disable the proprietary compression technology for PACTOR-II, PACTOR-III, and PACTOR-IV modems and instead relies on the open FBB protocol, also widely used worldwide by packet radio BBS forwarding systems. Controversies and US regulatory issues In May 1995, the American Radio Relay League (ARRL) privately asked the FCC to change Part 97.309(a) to allow fully documented G-TOR, Clover, and original open source PacTOR (Pactor I) modes. The FCC granted this request in DA-95-2106 based on the ARRL's representation that it had worked with developers to ensure complete technical documentation of these codes were available to all amateur radio operators. However, subsequent versions of Pactor contained proprietary compression algorithms that prevent over-the-air interception. In 2007, a US amateur radio operator filed a formal petition with the Federal Communications Commission (FCC) aimed at reducing the signal bandwidth in automatic operation subbands; but,