Remember to dot your "I's" and cross your "T's." A mansion in unincorporated Chatsworth that sustained $3 millions in fire damage early yesterday morning had an outdated phone number attached to its alarm system. Starting last Saturday, two days before the fire, any local calls made within the 818 area code required 1-818 before dialing local numbers because of the new 747 area code overlay. The auto call to alert the local fire department never made it, which may have caused a delay in their arrival. Because the home was inside a gated community and initially there was low water pressure, firefighter's response times attack on the fire was additionally delayed. All four occupants of the house escaped safely and one firefighter broke his ankle.