Nope, it's not a zip code. It was the identifier to my job in the US Air Force (1969-73). It identified me as a Special Electronics Technician in the 1035th AFTAC, or Air Force Technical Applications Command with headquarters then in Alexandria, Virginia.
More specifically after basic training at Lackland AFB in San Antonio, Texas and training at Lowry AFB in Denver, Colorado, I was attached to the 1155th Technical Operations Squadron at McClellan AFB (Air Force Base) north of Sacramento, California west of North Highlands.
My job was in depot engineering and maintenance for the worldwide network of field stations for the various system used to monitor the nuclear test ban treaty. That was our mission, to watch the world for nuclear tests and assemble a complete picture about the bomb.
I spent the rest of my four-year duty there except for a few temporary duty assignments to Edwards, AFB, California, Eielson AFB, Alaska, Alexandria, Virginia, and Hamburg Germany (actually a small town outside the city I can't remember the name).
I was scheduled to go on tour to Aukland, New Zealand, Alice Spring, Australia and Chang Mai, Thailand but my boss changed the orders the week we were supposed to leave as he wanted the trip. He was reassigned when he returned from the trip for changing the orders preventing me from going.
My job was intitailly in the maintenance shop for the equipment for the H-System or magnetic and electrical systems used to detect nuclear explosions. There were 8-10 different systems with two additional airborne and one sea-based systems.
The field sites using the H-System were in Thule, Greenland, Edwards AFB, California, Alexandria, Virginia, Hamburg, Germany, Punto Arenas, Chile (closed 1970), the Shah's Wildlife Reserve, Iran (closed in mid-1970's), Alice Springs, Australia, Aukland, New Zealand, Chang Mai, Thailand, and the test facility at McClellan AFB, California.
All equipment was repaired at the depot at McClellan AFB and shipped to the field sites. Field sites were not allowed to repair equipment but to operate 24/7 and to remove and replace any equipment which failed to operate correctly. Later I was transferred to engineering where I developed, built and tested new equipment with the scientists.
Some of the equipment was used by other system, mostly the seismic system which was very similar to earthquake monitoring and detection systems used then and today. The chart Helicorders still in used for graphic display of seismic data was developed in part during the 1960's from this program and system.
[Note.--The graph is not an ink on paper recording. The paper is three layers of a base paper layer, carbon black layer and a top layer of burnable paper. The "pen" is a heat element powered by 450 volts DC to burn the trace through the top layer exposing the carbon trace. This makes the trace permanent and can't be smudged, erased or ruined in any way. The tics are 10-second intervals.]
Anyway, it was a fun job but in the end I always remembered that the mission of 1155th TOS was to identify, locate and reconstruct nuclear explosions, and in the event of a nuclear war, we were the score keepers. We could detect any nuclear explosion on the earth or moon, meaning anywhere underground, on the surface, underwater, and atmospheric.
Scary thought then but we all survived.