Machine Numbers

Everything you need to know about OTIS Machine Numbers

Otis assigns a unique ID to each elevator and escalator, similar to an automobile VIN. This number is called sales number, contract number (not to be confused with Mod contract numbers), or machine number.

Traditionally, the material for each shipment from an Otis factory was marked with this unique number to identify the hoistway where the material was to be installed. The best place to find the machine number on an existing elevator (marked Sales Number) is the controller data tag, the crosshead data tag, and/or the hoist motor data tag. While other items may have a machine number marked in crayon or paint, or on a paper label, only these three locations have a consistent tag with the machine number shown.

Very early vintage units (very early 1900s) have 4- or 5-digit machine numbers. Otis then began using 6-digit machine numbers, which continued until approximately 2020. It is assumed that the earliest machine numbers were recorded in a ledger in the Yonkers factory and assigned in the order in which contracts were received. As Otis expanded operations, blocks of machine numbers were assigned to regional offices. The regional office assigned the machine numbers to each new elevator sold from their assigned block of numbers. For example, machine numbers 273000-274999 were assigned to the Southeast Region to be administered and assigned by the regional headquarters in Atlanta. One exception are numbers 400000-499999, which were used exclusively for LRV contracts shipped from Bloomington factory in the 1990s.

In approximately 2020, Otis changed to alphanumeric string for machine numbers for new installations. The machine numbers start with the sequence "N1" followed by four alphanumeric characters issued in sequential order as contracts are assigned. When the contracts were initially loaded into EIM system, the letter "N" was not allowed, so those machine numbers were entered as "U1xxxx" in EIM.

Although no longer common, machines and controllers have sometimes been moved from one building to another, sometimes to different cities and states. As such, the original records for a given machine number may not match the physical address where some equipment is presently installed. In many cases, the Otis machine records contain notes pertaining to the move.

Some Otis machine numbers begin with a letter, such as C, D, or Z. These machine numbers were assigned when Otis modernized a competitor unit, took a competitor unit on service, or when Otis bought another elevator service company. The following table provides guidance on how the letter-prefix machine numbers were assigned.




Elevators acquired with the purchase of Bay State Elevator. These should also have an Otis 6-digit machine number assigned.


Original prefix for competitor units. Assigned when the elevator was brought to Otis for maintenance or modernization.


Competitor-installed units (overflow from C when the numbers ran out)


Competitor-installed units (overflow from D when the numbers ran out)


Competitor-installed units (overflow from F when the numbers ran out)


Competitor-installed units (overflow from G when the numbers ran out)


Elevators acquired from the Otis-purchased companies, such as Unitec and Vertech (NY).


Elevator acquired from Otis-purchased companies, such as Delta-Beckwith (MA) and Amtech (CA).
Some very old Otis elevators, whose records were lost, were also assigned Z-prefix numbers.
Some older elevators that were maintained by another company that was eventually purchased by Otis were then assigned a Z-prefix number, as well as their original Otis number.