What Is T-Mobile MCC/MNC?by Lara Webster
Global System for Mobile Communications (GSM) networks are used with digital cell phones, connecting the devices to cellular service. Each cellular network is assigned a unique code or codes, called the MCC/MNC, which identifies the phone to that specific GSM network. T-Mobile is among the U.S. providers to use MCC/MNC numbers.
The MCC portion of a MCC/MNC code stands for the Mobile Country Code. The MCC helps the GSM network identify the device's home location -- wherever the user signs up for service. The MCC code is used internationally. Each MCC code has five to six digits, the first of which identifies a general region for the phone. For example, a device with a MCC that starts with "3" will always be from North America or the Caribbean.
MNC stands for Mobile Network Code. The MNC is a part of the MCC; while the first three digits of the MCC identify a phone's location, the MNC attaches the phone to a particular cellular network, such as T-Mobile. The MNC is either two or three digits long. In the case of T-Mobile, the MNC is always three digits.
There are several country codes assigned to the United States; T-Mobile uses 310. The MNC portion of the MCC may vary depending on the region of the T-Mobile user within the United States. For instance, T-Mobile in Hawaii has its own MNC: 250. MNC codes that are used more broadly in the U.S. are 290, 280 and 300.
Your T-Mobile cell phone is automatically assigned a MCC/MNC number when you activate it on the GSM network. Attempting to alter the codes on your phone may result in the device no longer being able to communicate with the T-Mobile GSM network, which stops your cell phone service.