Phone[…](1):=
u_to_p  ! 1 ! Offhook;
p_to_s ! 1 ! Offhook;
s_to_p  ! 1 ! Tone;
u_to_p ! 1 ! Dial ? Dest:num;
p_to_s ! 1 ! Conreq ! Dest;
s_to_p ! 1 ! Connect;
stop
Switch[…] :=
p_to_s ? O:t ! Offhook;
s_to_p ! O ! Tone;
p_to_s ! O !conreq ? Dest:t;
s_to_p ! Dest ! Ring;
p_to_s ! Dest ! Answer;
s_to_p ! Dest ! Connect;
s_to_p ! O ! Connect;
stop
Phone[…](2):=
s_to_p ! 2 ! Ring;
u_to_p ! 2 ! Answer;
p_to_s ! 2 ! Answer;
s_to_p ! 2 ! Connect;
stop