simple check problem

[shrinivas.bura]

I had set an item with simple check for to check whether SSH is available as below
ssh,22

I had set trigger so that whenever SSH is down for 120 secs i should get sms alert
trigger is set as below

ace.logix.in:ssh,22.min(120)=0

But i think this doesn,t seems to work i had get few alerts thjat SSH is down but i was still getting ssh to server also alert came immediately after zabbix is showing Down not after 120 secs
can somebody check what is missing in configuration

[Alexei]

ace.logix.in:ssh,22.max(120)=0