TAC (Type Allocation Code) is an 8-digit code at the beginning of IMEI number that identifies cellular devices, including its manufacturer, model number, and regulatory approval.
TAC, IMEI, and ICCID serve distinct purposes in the telecommunication industry and are associated with different components of a cellular device and a SIM card.
IMEI (International Mobile Equipment Identity)
IMEI is comprised of 15 digits that form a unique identifier for each cellular device. It comprises the first 8 digits as the TAC code and the last 7 digits as a unique serial number. IMEI's primary purpose is to provide a unique identity to a mobile device within cellular networks. This allows for blacklisting in cases of theft or misuse. Regulatory bodies or GSMA-approved organizations assign the TAC code. Here's a sample IMEI number with the first 8 TAC digits underlined: 358719060123456.
ICCID (Integrated Circuit Card Identifier)
Typically 19 to 20 digits long, ICCID identifies the SIM card itself, not the device using it. ICCID is utilized by cellular networks to recognize the SIM card and associate it with a specific subscriber account.
Every legally manufactured and sold cellular device possesses a unique TAC assigned to it. The TAC is an essential component of a device's identification, providing information about its manufacturer and model.
Certain device models may have many TACs associated with them due to variations in manufacturing location, timing, and other factors. However, each individual device will have only one unique TAC. For example, an iPhone 5S may have 21 possible TACs, but each iPhone 5S unit will possess only one TAC.
TAC numbers are primarily linked to the modem or module used by the device to access cellular services, rather than the specific device type. This means that devices with different purposes, such as a smart meter and a crop sensor, might share the same TAC. In such cases, the network relies on other IMEI digits to identify individual devices.
The TAC is commonly utilized in cellular devices, while with IoT devices and systems that do not rely on cellular communication, TAC may not be necessary. For instance, technologies like Low-Power Wide-Area Network (LPWAN), Wi-Fi, Bluetooth, or Zigbee have their own mechanisms for device identification and communication. Among the other alternatives to cellular identification and TAC are:
Unique Device Identifier (UDID)
UUID (Universally Unique Identifier)
MAC Address (Media Access Control Address)
Device Serial Number
Application-Specific Identifier
Device Certificates
User-Defined Identifiers
