-\langle s_i, \mathcal{OUTN_{SO}}(s_o),\mathcal{OUTN_S}(s)\rangle\\
-{[inchar_{sos}]} \qquad &
-\langle inchar, s_i, s_o, s\rangle \Rightarrow
-\langle s_i, s_o, s\rangle\\
-{[outchar_{sos}]} \qquad &
-\langle outchar, s_i, s_o, s\rangle \Rightarrow
-\langle s_i, s_o, s\rangle\\
-{[switch_{sos}]} \qquad &
-\langle switch, s_i, s_o, s\rangle \Rightarrow
-\langle s_i, s_o, s\rangle\\