THE THREE TONES
===============

The tones from Channel 33 are not an alarm. The notebook, the cassette
and the service cabinet agree: they are a synchronization sequence.

Tone one identifies the station.
Tone two identifies the maintenance window.
Tone three closes the outward path.

The fourth tone never plays because it would synchronize the node with
the rest of the network.

You write the sequence on the back of a relay tag. The ink disappears,
then reappears on a display below:

    SYNC COUNT: 4 / 33
    WAKE THRESHOLD: 7