+=head1 PROTOCOL
+
+Each byte of the data string is converted into its bits sequence, with bits of highest weight coming first. All those bits sequences are put into the same order as the characters occur in the stream. The emitter computes then the longuest sequence of successives 0 (say, C<m>) and 1 (C<n>). A signature is then chosen :
+
+=over 4
+
+=item If C(m > n), we take C<n+1> times 1 follewed by C<1> 0 ;
+
+=item Otherwise, we take C<m+1> times 0 follewed by C<1> 1.
+
+=back
+
+The signal is then formed by concatenating the signature, the data bits and the reversed signature (i.e. the bits of the signature in the reverse order).
+
+The receiver knows that the signature has been sent when it has catched at least one 0 and one 1. The signal is completely transferred when it has received for the first time the whole reversed signature.
+
+=head1 CAVEATS
+
+This type of IPC is highly unreliable. Send little data at slow speed if you want it to reach its goal.
+
+SIGUSR{1,2} seem to interrupt sleep, so it's not a good idea to transfer data to a sleeping process.
+