hh3cEntityExtManuSerialNum 1.3.6.1.4.1.25506.2.6.1.2.1.1.2

Manufacture serial number. The manufacture serial number of the entity such as chassis, module, and so on. It is got from the device when manufacturing. For low level box-device, the manufacture serial number is the device-number of System Control Board(SCB for short), it is written into the SCB directly; for middle level or high level frame-device, the manufacture serial number is the device-numbers of SCB and Service Board, because the SCB, Service Board and chassis are separate to sale and the device-number of chassis cannot be written into board.