I was on a 72 hour shift (from 6am friday morning to 6am monday morning),and was sleeping in the back of the unit (cuz it was comfortable),and I thought I heard our service's tones go out,so I got up and jumped out the back of the unit and jumped in the cab,started it up,and pulled it out. The minute I got the unit out on the curtain I radioed to county dispatch advising them that I was clear on the call and in service. They radioed back and advised they were not aware of any call for us,so I acknowledged them and pulled the unit back into the bay and went to the department radio room and phoned in to dispatch and advised them of what happened,and you would not believe how blushed I was,I was so embarrassed,and with the fire chief right across the road,he heard the unit get pulled out and the radio traffic. So I went back to bed and the next morning,the chief came over and asked if we had a call and I explained to him what happened,he got a kick out of it,and so did I,just alil though.