What devices use 00203D?

Any network device with a MAC address starting 00:20:3D was manufactured by or for Honeywell Environmental & Combustion Controls.

MA-L · OUI prefix

Honeywell Environmental & Combustion Controls

Q: Who owns MAC prefix 00203D?

00203D is registered to Honeywell Environmental & Combustion Controls in the IEEE MA-L registry.

Any MAC address starting 00:20:3D is registered to Honeywell Environmental & Combustion Controls in US.

OUI prefix	00203D
Vendor	Honeywell Environmental & Combustion Controls
Registry	MA-L (24-bit, large block)
Country	US
Example MAC	00:20:3D:00:00:00

What this means

The IEEE assigned the MA-L block 00203D to Honeywell Environmental & Combustion Controls. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 00:20:3D, it is Honeywell Environmental & Combustion Controls hardware.

Look up another MAC