C24 tone info


"(C-24) Designed by stations; fine-tuned by stations. This service was designed to meet stations' needs in a rapidly changing financial climate. As station needs evolve, so does Classical 24. We work with your local public radio station to achieve success."


Several stations including WMRA desired to use the triggers for ID-1 and ID-2 breaks simultaneously for their automation system. The decoder unit will not do this in its current configuration. Therefore, a modification was sought.

Automation of the 00's, not the 80's.

The C-24 decoder is a simple device, made to interface with cart automation. The unit will actually function as a complete automation system, and in many cases might not even be located in the station's studio, but in an equipment rack with a single cart machine. Unfortunately, many (most) stations no longer even use carts. All spot announcements at WMRA are digital files on NT workstations.

The concept of the decoder is that stations would decide if they were going to use a :90 break (ID2) or a :20 break (ID1). With C-24 the first :70 of the :90 break is "covered" by the network with fill music. This, in automation parlance is an "optional availability". The :20 break (ID2) would be called a "mandatory break", as it is not covered. In most automation systems, the mandatory breaks would always be programmed with spots and the optional availabilities would be programmed with spots when the traffic load or daypart requirements so indicated.

However, the C-24 scheme, designed around a crude "cart based" paradigm, requires that you either take the entire :90 as one break, or just the :20. This will become evident as we discuss how the program log is set up in a typical automation system. As it stands, unless an employee manually punches the ID1 and ID2 buttons, there is no way to toggle between long and short breaks. In other words, in an unattended situation, there is no way that one can take a :90 break (:70 +:20) at the top of the hour, and :20 breaks during the remainder of the hour.

Many stations are currently using PC based automation systems that even import the "traffic log" (underwriting schedule) and automatically place those spots. It is also a common practice to run underwriting spots in the evening, but not between Midnight and 5 AM. The current C-24 decoder does not allow stations to utilizes this flexibility.

The Program Log

A typical program log for C-24 automation (current scheme) looks likes this


Note that under this scheme, the ID2 (optional availability) is used only when desired, and that it can be used during some breaks or dayparts and not others.

Product Rotation and Operational Constraints

Under the current C-24 scheme, with [ID2] selected, the entire :92 break is essentially one cart, or one wave file in the most basic configuration. In order to obtain rotation, each combination of Liner and UW credit would have to be recorded together. Practically speaking, only a limited number would be recorded. So every time you hear the Acme Funeral Home spot, you hear the liner promoting ATC as well.

The time spent in compiling these complete breaks would be excessive.

With [ID2] selected, you could indeed sequence a series of spots totaling :92. But you could not stay with the network and utilize only the :22 mandatory break [ID1] on occasion unless you relied on some sort of timer to hold the network in for :70 seconds. Which would cause real problems if the network timing was not exact. Sure, a silence sensor could hold the fade until silence was detected, but we are now talking about adding layers upon layers of unreliability.

Under the proposed scheme, each liner, weather forecast, legal ID and UW credit would be recorded ONCE, and would remain a separate file, just as they are separate items on the program log. Each of these program elements could be in an independent rotation. With 10 liners, 2 weather forecasts, and 30 UW credits , you would have 600 possible combinations. And, of course, spots would be recorded in the voice of the current host, with the automation system making the changes in the files played at the appropriate shift change times. We are looking at a system then that sounds as good or better than a live shift.


Here are the instructions for a simple, non-destructive, depot-acceptable modification supplied by MPR's Ralph Hornberger:

Remove the top of the chassis. With the front of the chassis towards you, look along the front left edge of the circuit board. You will see four areas labeled ID1, ID2, ID3, and ID4.

There are five sets of pads in each of them and jumpers in the pads as follows, counting from the top: ID1: 1 &2 ID2 1 & 5 ID3: 1,2 & 4 ID4: 1,2,3, & 5.

What you need to do is to cut all but the number 1, or top,jumper in each of the four areas. This will shorten the length of the timer that controls both the audio switcher and the second tone hold off circuit. The latter is what prevents the decoder from seeing the second (20 second) command sequence when the 90 second (ID2) button is depressed.

(snip each jumper carefully in center so that thay may easily be resoldered should conversion back to the original mode be required -ed.)

To use the modified decoder, depress both the ID1 and the ID2 buttons. When a break occurs, you will first see the ID2 lamp light for about 10 seconds; before it would have stayed on for the full 90 seconds. Seventy seconds into the break you will see the ID1 lamp light for 10 seconds. When each lamp lights, its associated relay will close for about 1 second.

I should note that the audio switcher will no longer act properly; it will switch to the ID1 and ID 2 sources for only the duration of the lamps.

(Use this type system where network audio and local audio are routed through a sound card such as an antex SX-36 in a wavestation system -ed.)


The modification should take less than 5 minutes start to finish. Use both the ID1 and ID2 closures to trigger your automation. I would suggest NOT switching the ID buttons as your programming needs change, but rather handling the optional breaks in to your automated program log. For wavestation, this can be accomplished with a dummy "spot" in the :70 position when you don't want to take the availability. This dummy spot can either be a REM macro (REM - STAY WITH NETWORK) or a .1 second blank wave file (staywithnetwork.wav).

Switching back and forth between ID1/2 and ID1 will lead to operator error, and that is why we are automating in the first place- to get away from that!

BE KIND TO YOUR DEPOT! Make a note on the back of your business card that the unit has been modified and tape it to the chassis.

If you utilize this modification, please drop me a note. Thanks.