Redirect all incoming call to ivr

Hi all,

i search for days to ask my questions but i don’t find anything,
i need to redirect all incoming call from an specific extension 88880 to ivr. I create the IVR from web gui. now how to redirect call to ivr just created?

i try

exten => _88880,1,Dial(SIP/${EXTEN})

And call the sip 88880 but in this sip i configure the ring time to 1 then go to IVR but nothing.

Someone have an idea?

ps: Sorry for my bad english, i hope i find any help thanks in advantages