The EIA/TIA 41 specification (formerly known as IS-41D) is primarily used in the wireless network to provide services like automatic roaming, authentication, intersystem hand off, short message service, etc. All wireless network elements like the MSC, HLR, VLR, SMSC, EIR and AUC use this messaging protocol to communicate among themselves.
 
The IntelliNet ANSI-41 API facilitates building platform-independent, transport-independent and vendor-independent applications. Applications include all wireless entities such as the Mobile service Switching Center (MSC), Home Location Register (HLR), Visitor Location Register (VLR), Message Center (MC), Equipment Identity Register (EIR), and Authentication Center (AC). These entities assist in API functions including registration, deregistration, MS inactivity reporting, authentication, basic feature processing, and automatic roaming maintenance. All wireless network elements use this messaging protocol to communicate. The application encodes and decodes the message using the ANSI-41 library.