Enterprise IDs are available at http://www.iana.org/assignments/enterprise-numbers . For example, Cisco is 9 (i.e. 1.3.6.1.4.1.9). You would first need to identify the enterprise associated with your device, then you would need to contact that vendor to tray and ascertain what type of device it is. That said, often times, you can stick the sysObjectID in Google, and it will spit back the device type.
