I've mentioned it in a few of my previous posts, but the Launch Facility SIN line appears to be more of a factor in the Echo Flight case. It also appears to be a source of confusion for those attempting to make sense of the claims that a UFO was the cause of Echo's ten missiles to shut down. I want to describe for the reader what is the Secure Intersite Network (SIN) line, it's operational purpose and why it plays an important factor in any researcher's attempt to study this fascinating UFO case.
The Secure Intersite Network (SIN) line was a communication link between a flight's Launch Facility(LF) and it's Launch Control Center (LCC). The SIN line allowed the missile launch crew to talk to a maintenance team either inside the missile silo or inside the Soft Support Building (SSB) that was located partially underground adjacent to the silo enclosure. As far as I can recall, there were two SIN line connections inside the silo and one connection inside the soft support building. For clarification the soft support building contained all of the Launch Facility environmental equipment, ie, chiller/air conditioning equipment for LF equipment cooling air, applicable supply for heating source, and the diesel motor generator as a source for back-up power in the absence of commercial power.
In the silo itself, the SIN line was basically a headset with microphone and a tethered wire line that plugged into an audio outlet. The maintenance team member simply blew into the microphone to activate the line and rang the LCC. The LCC had two Telecommunication Consoles consisting of one located on the crew commanders status console and another located on the deputy's console. There were ten push buttons labled for each LF. When activated the buttons would flash and an audible ring would sound. The missile crew simply pushed in the flashing button and communicated with a typical hand held phone. By use of other push buttons, the crew could patch in a call from an outside line to the SIN line. This was used by Wing Job Control to talk directly to the maintenance team.
Now that I've given a crash course on the SIN line, why is it important to the Echo Flight case? The maintenance team that reported the UFO to Walter Figel had used the SIN line to make the observation. Per Walter Figel to Rober Hastings in 2008:
WF: [When] the missiles dropped off alert, I started calling the maintenance people out there on the radio to talk to them. I had the security guard authenticate so I know I’m talking to a security guard and, you know, [I asked] “What’s going on? Is maintenance trying to get into the silo?” [The guard said,] “No, they’re still in the camper.” [So, I said,] “Get ‘em up, I want to talk to them.” Then I tried to tell them what I had was a Channel 9 No-Go.
WF: Uh, we did that with the sites that were there, that [had maintenance teams and their guards on site] and I sent Strike Teams to two other sites. There’s no sense sending them where I [already] have a guard and a gun and an authenticate.
RH: So far in this narrative, you haven’t mentioned UFOs.
WF: [Laughs] That’s correct. Um, somewhere along the way, um, one of the maintenance people—cause he didn’t know what was going on any place else either, they have no capability of talking to each other [at different launch sites], in other words, they can talk to the [launch] capsule but they can’t talk to each other—
WF: —unless they were on the radio and no one was using the radio except the security police. And the guy says, “We got a Channel 9 No-Go. It must be a UFO hovering over the site. I think I see one here.” [I said,] “Yeah, right, whatever. What were you drinking?” And he tried to convince me of something and I said, well, I basically, you know, didn’t believe him. [Laughs] I said, you know, we have to get somebody to look at this [No-Go]. [A short time later] one of the Strike Teams that went out, one of the two, claimed that they saw something over the site.
Walter Figel went into a lot of detail describing for Robert Hastings how the maintenance team had communicated to him via the SIN line, not the VHF radio, since the only ones using the radio at that given time would have been the security personnel. Did the maintenance team have radio capability? Yes, each maintenance vehicle usually had a radio for communicating with Job Control and other base agencies. Could the maintenance team have been contacting Figel via radio? No, in order for the maintenance team to have verified the VRSA channel 9 LF No-Go, they had to have been inside of the LF's silo communicating via SIN connection with the LCC. Could the maintenance team have any visual observation field? No, they were inside of the LF with the launcher closure door closed.
Based on above, now the importance of the SIN line comes into to full view and why it is an important aspect of the Echo Flight case.