Margin Call is a level at which ForexCent company will inform trader about low level of Equity. If Equity due to loss trade will go lower to StopOut level, all opened orders will be closed.
ForexCent company inform trader about low Equity level by Margin Call - orders will be marked by Red color in Trading Terminal if Equity level is lower then Margin Call level. You can also receive e-mail with Margin Call notification.
To prevent automatic closing of all opened orders, trader should deposit additional funds to raise Equity level or to close unprofitable orders. Also you can request higher leverage if it is not high enough on your trading account. On forex micro account ForexCent company have 30% MarginCall level and Real forex account have 60% Margin Call level