Jurors heard the 911 call Mark Duenas made following the moments his wife was discovered dead.
The prosecution claims Mark admitted to killing his wife of nearly 33 years, Karen Duenas during the first 13 seconds of the call.
A retired SHASCOM employee as well as a current SHASCOM employee testified about how the 911 operating system works and how a copy of the call was made.
The first call was made at 12:56 a.m.
When Mark heard the call on Friday he kept his head down, arms up and seemed to be covering his ears.
The prosecution claims Mark said, "I killed my wife, expletive, blood everywhere."
While the defense claims he said, "I found my wife sick, blood everywhere."
Due to the fogginess around those first 13 seconds the Judge allowed the beginning to be played a second time and with personal earphones.
12 jurors and five alternates each took their turn listening.
The second eldest son, Jacob Duenas, also testified.
He said his mother had confided in him about her issues with Mark and told him about a texting relationship he was having with another woman.
Earlier in the trial, a deputy testified, shortly after Karen's body had been discovered he heard Mark on the phone say, "No I did not kill your mother."
When asked about it on Friday, Jacob said he could "not recall" asking that question.
In cross examination by the defense, Jacob said divorce between the couple had never been mentioned.
The trial will resume on Tuesday.