\begin{tikzpicture}[scale=.7]

    \tline{sc}{2};
    \tcaption{sc}{SystemC};

    \tline{ace}{0};
    \tcaption{ace}{P/T Solver};

    \draw (currentace) ++ (9,-.3) node {Simulated time};

    \ttimeline{sc}{10};
    \ttimeline{ace}{10};

    \tbox{sc}{1}{(1)};
    \ttextarrowU{sc}{end of instant $t_{i}$};
    \tcatchup{ace}{sc};
    \coordinate (sceoi) at (currentscL);

    \tskip{sc}{6};
    \ttick{sc};
    \ttextarrowU{sc}{next instant $t_{i+1}$};

    \tarrowCoord{(sceoi)}{(currentaceU)}{};
    \draw (tmpmid) node[anchor=east] {(2)};
    \tbox{ace}{6}{non-functional simu (3)};
    % \tcalloutL{ace}{No IT};
    \ttick{sc};
    \tarrowLU{ace}{sc}{};
    \draw (tmpmid) node[anchor=west] {(4)};
    % \tcalloutU{sc}{Continue};
    \tbox{sc}{1}{...};

\end{tikzpicture}

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