Margin calls and stop out levels are the same as any normal ECN Accounts. 

Margin call is that of 100%, while Stop out Level is at 70%. 

When the 100% margin is reached, a margin call will be triggered preventing to open new trades. 

If the 70% Margin or lower is reached, a Stop Out will take place at which the MT4 will start closing open positions simultaneously to prevent more losses leading to a negative balance.