Also, More information on this audio,

In the radio transmissions there are terms that you may not understand

So, This is the translation section

The word "K" or "Kay" is used meaning simply, "Over"

"10-60" Means Extreme Emergency/Disaster

"Box Alarm" followed by a 3-4 digit number is a specific preplanned designated location

Box alarms or grids are used by many FD's to simplify dispatching.

The "MCC" is a Mobile Command Center"

One FD officer tells the dispacher to initiate a "recall", this

means that all off duty firefighters are required to report

for duty because of some type of serious incident.

Also, it may seem like a lot of information is repeated from the trucks, well you're correct, It's because, by design the trucks can not hear each other they can only hear the dispatcher.

The simplest explanation is because at that time the FDNY radio system used two frequencies,

the mobiles transmitted on one frequency and the dispatcher transmitted on another which allowed the dispatcher to transmit and receive at the same time but not the vehicles. So, as a rule, the vehicles could not hear each other (there were few exceptions to this).

This was a 4-wire tone remote control system with Spectra-Tac voting.

You are hearing actual 'line audio' from the logging recorder input.