ARPANET (The Advanced Research Projects Agency Network) was the first wide-area packet-switching network with distributed control and one of the first networks to implement the TCP/IP protocol suite. Both technologies became the technical foundation of the Internet. The ARPANET was established by the Advanced Research Projects Agency (ARPA) of the United States Department of Defense.
The footage of Elizabeth watching US President Ronald Regan on TV was taken from his March 10, 1982 "Remarks on Signing the Afghanistan Day Proclamation".
Optical character recognition or optical character reader (OCR) is the electronic or mechanical conversion of images of typed, handwritten or printed text into machine-encoded text, whether from a scanned document, a photo of a document, a scene-photo (for example the text on signs and billboards in a landscape photo) or from subtitle text superimposed on an image (for example: from a television broadcast). Widely used as a form of data entry from printed paper data records - whether passport documents, invoices, bank statements, computerized receipts, business cards, mail, printouts of static-data, or any suitable documentation - it is a common method of digitizing printed texts so that they can be electronically edited, searched, stored more compactly, displayed on-line, and used in machine processes such as cognitive computing, machine translation, (extracted) text-to-speech, key data and text mining.
"Behind the Red Door" is a joke on the title of one of the big surprise hit films of the 1970s, Behind the Green Door, a porno.
The house number of Agent Beeman is 33-as revealed while he surveys his newly painted red front door. That is the age which John Belushi (whose death is mentioned in this episode) died.