Control Technology — 3 prefixes (MA-L, merged registrants)

The control-technology vendor slug is not a single company: it merges three separate IEEE MA-L registrants whose names all normalize to the same key after the pipeline strips corporate suffixes (Inc./Corp./Corporation). The three blocks are 00:C0:CB "CONTROL TECHNOLOGY CORPORATION" (Hopkinton, MA), 00:20:25 "CONTROL TECHNOLOGY, INC." (Knoxville, TN), and F8:9D:0D "Control Technology Inc." (registry address Oklahoma City, OK). The OUI page generator groups by the same normalized key, so a single /mac/vendor/control-technology/ page renders all three prefixes under one display name — which makes it important that the enrichment copy describe the distinct companies rather than pretend they are one firm. Two of the three are clearly identifiable, still-operating industrial-automation manufacturers: Control Technology Corporation (CTC) of Hopkinton, founded 1975, builds programmable automation controllers (2600XM, 5200/5300 series), digital/analog/motion I/O, an EtherCAT master module, and web-enabled control/HMI software; and Control Technology, Inc. (CTI) of Knoxville, operating since 1980, makes the CTI 2500 Series programmable controller system (positioned as a Simatic 505-compatible replacement), industrial PCs, I/O modules, power supplies, and communications adapters. The third registrant (F8:9D:0D, Oklahoma City registry address) could not be tied to a live company site at that address; the closest same-name manufacturer (control-tech.com) is now in Redmond, WA with a different product focus, so that entity's continuity is left Unknown. All three are industrial control system (ICS/OT) equipment vendors, a security-relevant device class, but no CVE or CISA/ICS-CERT advisory was found for any of them. Note: IEEE publishes no registration date for OUI blocks, and the company founding years are self-reported on each firm's own site — not registry facts.

IEEE assignment

3 MA-L prefixes → 00:C0:CB (CONTROL TECHNOLOGY CORPORATION, Hopkinton MA), 00:20:25 (CONTROL TECHNOLOGY, INC., Knoxville TN), F8:9D:0D (Control Technology Inc., Oklahoma City OK) [Confirmed] — IEEE MA-L

Slug collision

all three registrants normalize to the control-technology key after suffix stripping; the page generator merges them onto one vendor page [Confirmed] — repo this site's own tooling (slugifyVendor) + this site's own tooling grouping

Registry / block size

three MA-L (24-bit OUI) blocks; distinct assignees, not multiple blocks held by one company [Confirmed] — IEEE MA-L

Entity 1 — Control Technology Corporation (CTC)

25 South Street, Hopkinton, MA 01748, US; founded 1975; programmable automation controllers (2600XM, 5200/5300), I/O modules, EtherCAT master, Modbus TCP, web-enabled control/HMI software; active [Confirmed] — controltechnologycorp.com, modbus.org member directory

Entity 2 — Control Technology, Inc. (CTI)

5734 Middlebrook Pike, Knoxville, TN 37921, US; operating since 1980; CTI 2500 Series programmable controller (Simatic 505-compatible), industrial PCs, I/O modules, power supplies, comms adapters; active [Confirmed] — controltechnology.com, us.profinet.com member directory

Entity 3 — Control Technology Inc. (F8

9D:0D): registry address 7608 N Hudson Ave, Oklahoma City, OK 73116, US; could not confirm a live company site anchored to that address; closest same-name firm (control-tech.com, Redmond WA, powered drive wheels / guard-rail systems) is a plausible-but-unverified match; current status Unknown

[Likely] — maclookup.app (F8:9D:0D), control-tech.com

Company status

CTC (Hopkinton) and CTI (Knoxville) active; F8:9D:0D registrant status Unknown [Confirmed for two; Unknown for third] — company sites

Device types

industrial control system (ICS/OT) equipment — programmable/automation controllers (PLC-class), I/O modules, HMI/automation software [Confirmed] — controltechnologycorp.com, controltechnology.com

Registration date

none — IEEE publishes no assignment/registration date for OUI blocks; any third-party "date registered" (e.g. maclookup.app) is a database artifact, not an IEEE fact [Confirmed] — IEEE the IEEE MA-L registry columns (Registry, Assignment, Organization Name, Organization Address)

Security context

no CVE or CISA/ICS-CERT advisory found for any of the three registrants; state as an honest null, not "no vulnerabilities exist" [Unknown] — cisa.gov ICS advisories (no matching entry found)

Analyst note

this is a merged-registrant vendor page; the correct honest framing is "several distinct manufacturers share this normalized name," with CTC and CTI as the substantive, verifiable firms and the Oklahoma City registrant flagged as uncertain — do not assert continuity between them.