The SR5048 by Spirent is a test configuration unit (TCU) that serves as an essential component of the 8100 Mobile Device Test System, functioning within a larger location test system (LTS). It offers compatibility with both GPS and GSM/WCDMA interface parameters through an N-type connector. When used with handsets featuring a single connector for combined GPS/cellular signals, the GPS interface of the SR5048 supports A500, A600, and B-Series platforms. The GSM/WCDMA interface, on the other hand, is compatible with A500 and A600 platforms.

One of the key functions of the SR5048 is to facilitate the LTS Calibration Procedure, which achieves highly accurate power level measurements at various points within the system. This semi-automated procedure quantifies the insertion loss across different signal paths and stores the collected data in a Microsoft Access Database. The SR5048's displays enable easy navigation through the calibration features. The calibration process encompasses steps such as initializing setup information, calibrating power meter sensors A and B, calibrating power levels to cable endpoints (C2, C1B, C2B, C18, C18B, P18), and post-calibration setup and data viewing.

To ensure seamless integration with the test system, the SR5048 is supported by the Instrument Configuration window, which provides a user-friendly interface for selecting different types of configuration units. This window offers several features, including check boxes to enable or disable communications with associated instruments, an address setting to match the GPIB or IP address configuration of installed instruments, a connection diagram display for the current configuration, and the ability to hide the connection diagram. Additional features within the SR5048's compatible configuration window include a communication check to verify connections between all enabled instruments, a details view providing information about enabled instruments, an OK button to save changes made and store them in the system registry, and a cancel option to discard changes and close the window.