The city uses a kind of in house intercom for dispatching as well as having radios on at all times in each station. Sometimes you may hear an apparatus respond on a call from their respective station and the captain may respond "*** responding, no audible." That means the voice dispatch was not received on the house intercom. Also, each firehouse has a (I think) a Walker Stand???? Don't quote me. Basically it is a closet sized room or maybe just a desk in the apparatus bay that at least one firefighter is assigned to monitor the radio, phone, log book and intercom etc. I believe most of this info to be true.
Hope it helps.