Seeing that again reminded me of a couple of questions I had about these. I understand the tone and the area. There are three "areas," duplicated in zones across the state. These areas have different DPS (base) and LEA pairs. For instance, Area 1 is 155.640/154.650 for DPS and 155.790/154.770 for LEA. Other areas use different pairs. The tones correspond to the different towers in the area. For instance, in my area, Tone A (127.3 Hz) is for the Storm Lake tower. Tone B (146.2) is for the Merrill tower. Tone C (167.9) is for the Matlock tower, and Tone D (192.8) is for the Terril tower.
But two things I don't know for sure:
1. What was tone E and when (if ever) was it used?
2. The "area" inner knob switches between "norm" and "alt". What was that for?
My guess (since I know they used to do this, but don't know how) is that "ALT" is for "talkaround" mode. In other words, not using a repeater, transmitting and receiving on the output of the repeater. I also have heard that they would use an out-of-region "area," turn off the tone, and listen on the input fq on their scanners for a "secret" car-to-car channel. This may have been done before cell phones and before my time, as I had all the inputs and outputs programmed into my scanner and never heard a peep on the other ones unless I traveled to another part of the state where they were in normal use.
Anybody know for sure?