  There are few known universality classes of absorbing phase transitions in
one dimension and most models fall in the well-known directed percolation (DP)
class. Synchronization is a transition to an absorbing state and this
transition is often DP class. With local coupling, the transition is often to a
fixed point state. Transitions to a periodic synchronized state are seldom
observed. Recently a transition to a synchronized period-3 state that is not in
DP class is observed. We model it using a cellular automata model with states 1
to $n$. The rules are a) Each site in state $i$ changes to state $i+1$ for
$i<n$ and 1 if $i=n$. b) After this update, it takes value of either neighbor
unless it is in state 1. With these rules, we observe a transition to
synchronization with critical exponents different from those of DP for $n>2$.
For $n=2$, a different exponent is observed.
