The underlying mechanics of the Emergency Alert System have been the source of extensive debate recently. It's not a new subject, but interest was quickly renewed when news of a radio spot for gasoline company Arco included a modified EAS tone that caused some EAS units to decode the partial RWT header to be logged. Some attentive engineers investigated the issue and discovered the details, which we documented at RadioMagOnline.com.

The poor choice in marketing caused many to think about EAS again, especially with the near perpetual wait for FEMA to finally adopt CAP as its standard. Once the decision is made (I have heard speculation that the announcement will come at the beginning of October), many broadcasters are concerned with the now legendary 180-day clock that will begin counting down.

FCC Rules 11.55 and 11.56 mention the 180-day clock. 11.55 discusses how CAP could be implemented into state plans and how stations might receive those messages. 11.56 has the meat: “[A]ll EAS participants must be able to receive CAP-formatted EAS alerts no later than 180 days after FEMA publishes the technical standards and requirements for such FEMA transmissions.”

We knew CAP was coming. Some still question the reasons for implementing it, but the reality is that stations will have to comply with the change. If you attended the 2010 NAB Show you heard the CAP demonstrations (which you could not avoid hearing anywhere in the Central Hall). The technology and hardware exist. Similar demos (although hopefully not as loud) will be held at the 2010 Radio Show.

Some stations are already in complete or near-complete compliance. Stations that bought an EAS encoder/decoder within the last 12 months (and possibly longer) can very likely already decode CAP messages, although many newer EAS units will need a software update with the latest CAP protocol. Some estimates say 10 percent of stations are ready when the 180-day clock expires.

I hear complaints about the unexpected cost of replacing EAS equipment. It's hard to call it unexpected at this point. The notice of the 180-day clock has been in place for more than two years. Granted, some stations operate on tighter-than-tight budgets, but this is an expense that should have been planned for by now. While no one likes to scrap equipment that works, the current EAS was designed 15 years ago. That's a step away from stones knives and bear-skin huts in technology terms.

There are also several unknowns in how states and local agencies will transmit CAP messages. Much of the CAP rollout is a work in progress. But for stations, having the CAP-compliant EAS unit is the basic step. As engineers, we usually want all the details before installing a new system, but all the details are not yet known. If a state or local plan has no mention of CAP, a station obviously cannot fully integrate the system. But the CAP-compliant EAS unit can still be installed.

There have been pleas to extend the clock to 12 months or more, but even if the clock is extended to 24 months, many broadcasters will wait until the very last day before updating their equipment.

If nothing else, the 180-day clock puts a firm deadline on events that have already been put into action.