"Interoperability" is a big word with many different definitions depending on the context. In radio it means, broadly, the ability of operators or devices to communicate (that is, to exchange information) with one another. Interoperability normally refers to the characteristics of equipment rather than to operators although language and jargon also can be barriers to communication.

Public safety communicators have been grappling with the problem of interoperability for decades. When everyone used analog FM voice it was possible, in principle, to solve the problem simply by designating a common frequency. In practice it wasn't always that easy. Different agencies used different frequency bands, and even when they could get on the same frequency they couldn't talk very far and often used different jargon. The emergence of a variety of trunked and digital systems exacerbated the situation. Today there are technical solutions to the public safety interoperability problem -- but they depend on the availability of specific hardware, training, and a willingness on the part of agencies to relinquish control.

By comparison, Amateur Radio scores well in terms of interoperability. All CW stations built in the past 80 years are able to communicate with one other, assuming they have a frequency in common. The same is true of all SSB stations built in the past 60 years. (Historical note: The first amateur SSB transmission was made on September 21, 1947 from the Stanford University Radio Club, and the first two-way SSB contact was established on 20 meters between club station W6YX and W0TQK in Missouri on November 3 of that year.) On VHF FM, a newly minted operator with a brand new handheld transceiver can communicate with an old-timer who has used the same tube-type rig for the past 40 years.

Things get more complicated with digital modes. Codes and protocols become as important as hardware. As we move from the realm of hardware to software, maintaining interoperability becomes a greater challenge and does not occur automatically. A modern computer-based RTTY station can communicate with the old mechanical marvels, but only because they both use the venerable Baudot code. AMTOR stations can only communicate with other AMTOR stations. PSK31 is a remarkable development and a great improvement over Baudot-based RTTY for keyboard-to-keyboard communication, but its devotees can only communicate among themselves. With a few exceptions (the three versions of PACTOR are backward compatible and G-TOR is structured to be compatible with HF Automatic Link Establishment, or ALE) the HF data modes are independent islands in the digital stream. The story is much the same with regard to digital voice, which is developing more slowly except with regard to Internet-based internetworking such as IRLP and EchoLink.

For routine amateur operations, this is of no great consequence. We would like to be able to identify other stations that we encounter in the amateur bands and sometimes are frustrated by our inability to decode their transmissions, but this is a relatively minor issue most of the time. However, in emergencies we must be able to communicate with one another. If we do not maintain our interoperability within the Amateur Radio Service as we branch out in different digital directions, a call for help could go unheeded even if other stations are in range -- with potentially tragic consequences. In addition, the agencies we serve in responding to emergencies expect us to be able to communicate with one another, because we have done it so well for so long. Interoperability is one of Amateur Radio's distinguishing features; losing it would be a giant step backward.

This aspect of digital development has been a concern for some time, so it was reassuring to hear a series of presentations at the Third Global Amateur Radio Emergency Communications Conference (GAREC-07), held in Huntsville on August 16-17 just before the ARRL National Convention. In explaining how they are applying specific advanced technologies to emergency communications, speaker after speaker identified interoperability with other technologies and networks as a key objective.

It was a pleasure to hear how the VoIP Hurricane Net, www.voipwx.net, is utilizing both EchoLink and IRLP to provide "ground truth" reports to the National Hurricane Center.

It was encouraging to hear the proponents of D-STAR, Winlink 2000, and ALE all address the need to ensure that communication can take place between their platforms.

It was enlightening to hear how Army MARS is pursuing its mission of providing an auxiliary communications conduit for military, civil, and disaster officials during periods of emergency, and the steps already being taken to increase collaboration among the Army, Air Force and Navy-Marine Corps MARS organizations.

It was instructive to learn how disaster response organizations such as the American Red Cross, the Salvation Army, and Southern Baptist Disaster Relief meet their communications requirements using a variety of tools -- including Amateur Radio when appropriate -- and what they need from us now, which is quite different from just a few years ago. "Please send this spreadsheet to our headquarters" is an example.

Tying much of this together is the Internet. By its very nature, the Internet is able to survive a lot of disruption -- but connections to it from a disaster area may be non-existent at first and woefully inadequate, even via satellite, for hours, days, and possibly even weeks afterwards.

So it was a joy to share the GAREC experience with nearly 100 dedicated, committed Amateur Radio volunteers who were as intent on cooperating as on explaining and advocating their favorite technologies. This spirit of cooperation and the recognition of the need to preserve our interoperability bode well for the future of Amateur Radio emergency communications, and for our ability to continue to serve our local, national and global communities.

Previous: The K7RA Solar Update

Next: Sputnik and Amateur Radio