What does SPX stand for?

League City, TX - Location identifier - FAA (FAAL)

San Pedro - Colombia - Airport symbol (AD)

Sealed Power Corporation (EFIS)

Secured Packet Exchange (SAUS)

Sequenced Packet Exchange - Telecommunications

Sequential Packet Exchange (SAUS)

Simplex (UWER)

Simplex Circuit

Simplex Instrument - Telegraphy

Space Plume Experiment (SAUS)

Sparks, NV - Amtrak rail station code

Sphinx Engineering - NCIC firearms make code (NCIC)

Spirit Petroleum - Vancouver Stock Exchange symbol

Sportspal - NCIC boat manufacturer code (NCIC)

Stepped Piston Crossover (PDAA)

Superheat Power Experiment - Nuclear energy

Suspicious - Telegraphy (PCTE)

Spirex - Wire binding (DGA)