Murray Jackson, the police radio dispatcher, received an alert at 1:16 from the "citizen using the police radio".
According to a transcript of a recording made by a voice actived device.
we know that Murray Jackson (the dispatcher) was unaware of the shooting until 1:16
We only "know" this if the transcript of the recording made by a voice actived device is indeed accurate. So far it has never been proven to be, it is only assumed to be.
I believe that JAMES C. BOWLES Communications Supervisor Dallas Police Department explained the accuracy of the time in his interview in “No More Silence” by Larry Sneed:
Since I was the communications supervisor in charge of the dispatch office, I became involved with the tapes of all radio communications of the Dallas Police Department that day, the same tapes which were analyzed by the Warren Commission and later the House Select Committee on Assassinations. There should be no controversy about the tapes. The tapes are very simple and self explanatory if you accept them for what they’re worth...
...At the time of the initial investigation following the assassination, we impounded the tapes and held all records for just that purpose, the ensuing investigation. When the FBI took the tapes and tried to make audible sense out of them, they found that they couldn’t comprehend the tape traffic because they couldn’t understand the speech style used on the radio. The things that were said by the officers on the radio made complete sense to the officers, but they didn’t make a bit of sense to the transcribers. So an FBI agent brought the tapes back to the department, and the chief gave them back to me and asked me to transcribe them for him; of course, understanding that we didn’t have a lot of conspiracy theorists in our midst at that time...
...I just made a recording of it with a nice reel to reel tape recorder which the FBI furnished to me and then set about from the original tapes and the original Gray audiograph disks to transcribe the tapes using the originals because, according to the law, that’s the best evidence. The tapes were in as good a condition as you would expect considering the fact that the FBI had tried to transcribe them using a single stylus...
...Remember, even the House Select Committee and the National Academy of Sciences put in computer monitors on the belts and on the tapes so that the consistency of the tapes used indicated no interruption, alteration or changes. Both agreed as well as could be that the tapes at the last instance are the same as the original tapes in the first instance. No hanky panky!...
...Something a lot of people really got their lather up about was whether something was or wasn’t at a certain time. Some people tried to use stop watches to time that belt to say something happened after a certain minute, second, or fraction of a second. That is nonsense, utter nonsense!...
...The dispatcher had two types of clocks: He had a time stamp clock that didn’t show seconds, just minutes, and he had a digital clock in front of him which had the numerical hour and minutes. That was the usual clock for general sight and time statements. At the same time, the same dispatcher might use the digital clock. There was no way in the world that some six clocks in the telephone room and the two clocks in the dispatching room were synchronized. They could be as much as a minute or two apart. Usually we didn’t change them until they became at least two minutes or more out of synchronization of each other. There was one clock in the office that had a generally reliable time. It was on the back wall of the telephone room. The only trouble was that it was way back in the corner which you could hardly see, and nobody ever looked at it. It was just there...
...An officer, depending on the individual circumstance at an individual time, might use either the digital clock in front of him, or he might use the time stamp on the other clock. Using a headset, let’s say the dispatcher turns away to do something and in the process sees the digital clock and says, “224, a disturbance at such and such location—2: 13.” He used the digital 2: 13. By now the time stamp clock might be reading 2: 15. He puts it in the slot, turns around, and now 125 says, “I’m clear.” The dispatcher says, “125 clear,” and he looks at the time stamp—2: 15, “2: 15 KKB364.” Now it would look like to all the righteous world that 125 cleared two minutes after the radio operator dispatched the call at 2: 13, but he didn’t. It was almost in one breath. So, under no circumstance could you put any stock in the real world time or any continuity on time references by the belt because there were no time references on the belt; they were only spoken times, and those spoken times had no faithful validity...
...More specifically, at the time of the assassination, when Gerald Henslee, who was operating Channel 2, said, “12: 30 KKB364 Police Department, Dallas,” it really wasn’t 12: 30 by all that I can reconstruct by all other parallels. I used several indices to try to correlate that. There were certain places you could tend to lock Channel 1 and Channel 2 together such as things that transpired where there’s cross talk between the channels or where they used a simultaneous broadcast and went on both channels. I made a big, long sheet of paper where Channel 1 was on one side and Channel 2 on the other and slid these papers back and forth to try to line up conversation in a reasonably faithful lineup. A good close proximity is the best I could do—no one can do better.