According to Tom Voigt (I’d love to have him chime in on this), Zodiac spoke with the telephone operator FIRST. I believe her name was Ms. Johnson. The extent of that conversation is unknown because the phone company refused to cooperate with law enforcement. However, that interaction with Zodiac was long enough and apparently suspicious enough to have Ms. Johnson request a trace on the call from her supervisor (Betty Main?). That trace was initiated PRIOR to Zodiac being patched through to Nancy Slover.

This is a pretty much unknown detail. What did Zodiac say to the operator that would raise her suspicion enough to initiate a trace? Who is the operator? Who was her supervisor? Are they alive?

The phone company at the time had a strict privacy policy which is why they would not divulge any information about that call to the police – at least none that is known to the public.

I believe it takes between five and twenty minutes to trace a call back then, so it would make sense that if the trace was initiated prior to speaking with Slover, when Zodiac hung up the receiver, it would begin ringing back. This would seem to lend credence to Zodiac’s contention about being spotted by the "shabbily dressed black man".

What is known about the business at that location?

Was it a 24-hour operation? Was it a service station? A Phillips 66??? Do we know any of the employees of that business?

Locals called it Joe’s Union Service Station, address was 700 Tuolumne and Springs, although it was then Sylvia’s Union Gas Station. Then apparently Nick Houtz’s Union station later or something like that. Located on the northeast corner, It now occupied by a real estate office. My understanding was the the business was closed at that time of night.

Richard Grinell said;
How long do you think it took for the payphone at Springs Road and Tuolumne
Street to be rung back"…

(Note; I’m aware of your comments here;)
https://www.zodiacciphers.com/zodiac-ne … e-payphone
Richard Grinell said; "If the trace and ‘ringback’ had occurred almost immediately
(in under 10 seconds), why, bearing in mind the gravity of the murderous phone call,
did it take 6 minutes to relay this crucial information to police."

I think almost zero seconds. Zodiac also implies this in his August 4th 1969
‘Debut’ letter’; "When I hung the phone up the damn thing began to ring".

I understand the call was from a phone box via initially dialling the operator.
Although I don’t agree with Thomas Horan’s views on who may have made the
call, he does appear to have explored some of the technical aspects regarding
coin phone box calling in that era;
http://zodiachoax.blogspot.com/2013/07/
"In the TSPS days, if you made a TOLL call from a payphone, and owed more money
at the end of your call, then the phone company switching station would automatically
‘ringback’ that number and ask you to deposit more money. IF you didn’t, then the
system would call an operator and display the number you had called so that she could
have that number billed for the call. In case you thought you got away with it. BUT—this
could ONLY happen with toll calls, NOT free or emergency calls, since only the
long-distance access switch banks were equipped with the expensive billing and
ringback doohickeys."

It is unknown whether the telephone exchange operator console that Ms JOHNSON
was situated at had ‘RING BACK’ capability. I’m more favourable to the the idea that
it did have that capability than Thomas Horan, because Vallejo is cited;
https://en.wikipedia.org/wiki/Pacific_B … conversion
"To place calls to certain other Northern California exchanges, such as"…"Vallejo
in Northern California, dial customers would dial ‘’0’’ to reach an operator.
The operator dialed through a tandem switch and directly called numbers
in those cities."
A reading of a number of paragraphs of the wiki for tandem switches;
https://en.wikipedia.org/wiki/Class-4_telephone_switch
https://en.wikipedia.org/wiki/Class-4_t … ss_tandems
https://en.wikipedia.org/wiki/Class-4_t … ch#History
suggests to me the possibility that Ms Johnson could have been at a
telephone exchange that had, or she had familiar communication access to a
linked telephone exchange that had, the ‘Ring Back’ capability.

Anyway, to lay it out then, I see several possible scenarios;
Zodiac dialled the operator, said something like "HI! I’m the Zodiac/I’d like to
report several murders to the (such and such?) police" – Ms Johnson connected
the call to (such and such?) police, left her phone jack plugged into the call line,
and informed a supervisor of a desire to have the call traced.
a.) She listened in to the call – it is uncertain if the operator is technically able
to ‘listen in’, it may or may not be legally permissable, or allowed/disallowed
under the company’s policies, or
b.) She did not/was not able to listen to the call, however that lines call lamp
remained ‘lit’ to indicate the line was still in use (calling/called parties still ‘off
hook’) (Note; e.g. as seen here at 25:29 ; )
https://www.youtube.com/watch?v=uZs29HRWnWQ
and her phone jack remaining plugged in to the parties line (and she was
technically able/not able to access the audio occurring on that line).
__i.) Ms Johnson activated her ‘Ring Back’ switch, so she would automatically
electronically be connected to the called party once they went ‘on hook’ (i.e.
Zodiac hung up), or
__ii.) Ms Johnson monitored the state of that line’s call lamp and immediately
manually activated her ‘Ring Back’ switch when she saw the lines’ call lamp
extinguish, or
__iii.) Ms Johnson’s console had/had not a ‘Ring Back’ capabilty, regardless,
when she saw the lines call lamp extinguish, she immediately manually
activated her ‘Call’ switch (remember her phone jack is still connected) and
ring signal was sent to the (former) calling party (Zodiac now ‘on hook’)
causing the phone boxes’ telephone to begin ringing, or
__iv.) Ms Johnson’s supervisor arranged/caused, either at that exchange
or another connected exchange, a ‘ring back’ or ‘call switch’ to occur on that
line (either electronically automatically or manually).
z.) … which incidently, preserves the (connected) state of any mechanical
switches on that line, thereby enabling a ‘Call Trace’ to be actioned (-you
will probably dimly remember the advice current in those times, that if you
received a call which anybody wanted to report and be traced, to then NOT
hang up the phone (because hanging up the phone causes any mechanical
switches on the line to shortly disengage from their connected positions,
which makes tracing a call more difficult-to-impossible, in that era, if the
exchange had mechanical type switches).

We don’t know what the procedures were for a ‘Call Trace’, so the ‘Ring Back
or ‘call switch’ may have been a part of the procedure, or it may have been an
option additional to the procedure, or it may have simply been an initiative
taken on the part of Ms Johnson or her supervisor (which may/may not have
been specifically allowed in the companies policies).

So, although I realize that you are considering the possibilty that Zodiac hung
up and some time later the phone rang , which raises in your mind
the possibility that Zodiac lived ‘nearby’ and therefore could hear the distant
phone ringing – I hold a contrary view, that it is more likely that something
from the above scenarios occurred, and the phone rang pretty
much immediately as Zodiac hung it up.
Cheers
P.S 6 minutes might be a reasonable amount of time for the exchange staff
to action the Call Trace by checking the state of that lines’ connections,
either checking the mechanical switches visually or viewing electronic
visual indications, possibly refering to a record of what location that phone
box is at, and calling and explaining that information to whoever of the
police they contacted.

Chaucer asked;
"…telephone operator"…"I believe her name was Ms. Johnson."…"her supervisor (Betty Main"
…"Who is the operator? Who was her supervisor? Are they alive?"

If they lived in Vallejo, perhaps their names may be found in here;
https://www.zodiacciphers.com/zodiac-ne … e-payphone
Cheers

Great explanation Buyerninety, that sounds totally plausible. I wish it weren’t the case, then we may have something tangible. If only somebody had asked these pertinent questions to the operators at the time, or at least later and made it public. Not being allowed to make a statement should not have been an option.

I just wonder if Zodiac worked at that service station and had the ability to hide his vehicle in a repair bay or behind the business somehow.

I just wonder if Zodiac worked at that service station and had the ability to hide his vehicle in a repair bay or behind the business somehow.

Interesting…..I have never heard of that angle being explored…..worked there previously, but not at the time of the call?…I have been watching the Golden State Killer series and he committed crimes in some of the areas he was familiar with….maybe someone on the board has looked at that angle and can comment…worth a shot…

I’m hoping to revisit this aspect of the case.

Really wish Tom would pipe in since he has suggested that the interaction between the operator Mrs. Johnson and Zodiac was more substantial than a simple "Connect me to the Vallejo Police Department, please." They had to have had a conversation that raised enough suspicion or curiosity of Mrs. Johnson to request a trace immediately AND possibly listen in to the call.

I believe the phone rang the instant Zodiac hung it up. Whether the "negro" Zodiac described was real or a red herring to mislead police is another story…

I’m hoping to revisit this aspect of the case.

Really wish Tom would pipe in since he has suggested that the interaction between the operator Mrs. Johnson and Zodiac was more substantial than a simple "Connect me to the Vallejo Police Department, please." They had to have had a conversation that raised enough suspicion or curiosity of Mrs. Johnson to request a trace immediately AND possibly listen in to the call.

I believe the phone rang the instant Zodiac hung it up. Whether the "negro" Zodiac described was real or a red herring to mislead police is another story…

I retired from the telephone company. Back in those days they had operators working 24/7 in the central offices. The operator would ring the payphone right back immediately.

For what purpose?

Locals called it Joe’s Union Service Station, address was 700 Tuolumne and Springs, although it was then Sylvia’s Union Gas Station. Then apparently Nick Houtz’s Union station later or something like that. Located on the northeast corner, It now occupied by a real estate office. My understanding was the the business was closed at that time of night.

Still think its likely z pumped gas on the side or worked a used car lot…..doubt we ever find any employee records from gas station though

For what purpose?

I just thought about it. The operator would ring the payphone to ask for the money owed. That was when things were real and they had human beings work in the offices instead of DACS systems. That means the call Zodiac made was a toll call and money was owed by Zodiac. No other reason for the operator to ring back a phone, no other reason at all. So Zodiac called in state long distance or out of state long distance.

Unless it was a person to person call. The operator would standby to collect the fee at the call end.