Devices with MAC addresses that start with D4-21-22 were manufactured by Sercomm Corporation.

Device Manufacturer
Sercomm Corporation.

Manufacturer Location
3F,No.81,Yu-Yih Rd.,Chu-Nan Chen
Miao-Lih Hsuan 115

Estimated Devices using D4-21-22
16,256,250

Estimated Total Devices From Mfg
195,075,000