Type classification system
From Halopedia, the Halo wiki
Alien technology catalogued by the United Nations Space Command and Office of Naval Intelligence is classified by type number. Type classification is used by the UNSC to catalogue recovered materiel of Covenant origin in the Human-Covenant War, alongside that of the empire's remnants in the post-war era. For classifying spacecraft, the UNSC employ a three-letter system of identification analagous to humanity's hull classification symbols.
Type-classification is done in one of two ways. For the majority of materiel, the system is formatted as Type-XX or T-XX, with the latter two characters denoting to two numbers - usually signifying the year the item was classified. For example, a Type-25 weapon may have been classified in the year 2525. The UNSC method of classifying equipment by their year caused researchers no small headache as the war continued and new variants were catalogued and categorised, leading to numerous sub-classifications; some Type-classified weaponry also have sub-classification identifiers affixed to the end of their Type-designation such as the Type-25B brute shot or Type-56D needler. Equally, while much equipment was classified by the year of classification, this did not always respond to the first year the equipment was encountered. Some equipment such as the Type-56 Lich were employed sporadically throughout the war with humanity, but due to administrative delays or the battles not producing any surviving captured materiel to analyse, classification may be delayed for years afterwards.
While the vast majority of firearms and vehicles are sorted by the Type-year system, for reasons unknown the Covenant's melee weaponry and grenades are not, instead categorised as Type-X, with only a single numeric not corresponding to any particular year.
Type-classification of Covenant technology is a challenge for UNSC analysts, due to the way the Covenant categorises and uses its own technology. Rather than rigid standardisation as in the UNSC's armed services, the Covenant employ thousands of variations of a given design family, all roughly grouped as simply Shades or Wraiths. By contrast, the meticulous standards of human analysts ensure that almost every single minor variation of an equipment series goes catalogued even when the Covenant would not do so.
The Covenant themselves use design patterns to classify their materiel, ranging from the smallest firearms up to the largest supercarriers. Due to the differences in how both organisations classify equipment, design patterns generally do not always line up with UNSC classifications. For example, the UNSC type designation Type-52 Phantom was applied to two models of Phantom at different times, the Kez'katu-pattern and Ru'swum-pattern, with minor variations of the latter also being type-classified as the Type-44.
The majority of equipment classified after the year 2552 represents much of the equipment of Sangheili origin, employed during the Blooding Years by the Swords of Sanghelios, Jul 'Mdama's Covenant and other groups. Some of this equipment dates back to before the War of Beginnings, thousands of years ago.
A similar system for designating equipment of Covenant origin is also used by humanity in parallel with the Type-designations. Unlike the type-system, class-designations are used to describe families of weapon systems - predominantly the varying classifications of plasma cannons. Class designations typically designate their weapon type as Class- followed by a single-digit numeric suffix - usually a 1 or 2. These classifications generally seem to correspond (respectively) with the concepts of "light" and "medium" iterations of a given weapon system, though it stands to follow that a hypothetical "Class-3" may correspond with heavy iterations of the same weapon systems.
Class designations are also used by the UNSC to refer to human-manufactured equipment such as various Bumblebee models, or the Class-2 GMLS employed by the AV-14 Hornet, but it is unknown whether these two systems have any crossover.
List of class designations