Like I said earlier, if you DIT the trunks to the paging output, it will ring over your paging system.

If you set it to Night bell, the contacts should close on the ringing cycle. I have never used it, but per the manual, the contacts will close for 1 sec, then open for 3 sec. If you had a bell wired thru the contacks it should cause it to ring, as long as it rings by shorting the contacts.