The Data Collection Package (DCP) is responsible for receiving all of the raw sensor data from each individual sensor. It then transmits this data to the Acquisition Control Unit (ACU) for further processing and distribution.

Acquisition Control Unit (ACU): The ACU, which serves as the central processing unit for the ASOS, is typically housed within a climate-controlled environment such as an observing office or control tower. It ingests data from the DCP(s) and pressure sensors, and has the capability to accept information from the FAA's New Generation Runway Visual Range (NGRVR) system.

The ACU performs critical functions including final data processing, formatting, quality control, storage, and retrieval. It is the component that makes ASOS data available to various users through multiple distribution channels. 

Single Cabinet ASOS (SCA): The SCA is a modern solution that integrates the full functionalities of both the ACU and the DCP into a single, compact, and outdoor-rated enclosure. 

The Single Cabinet ASOS (SCA) typically includes a hybrid set of equipment from both the ACU and DCP, such as a VME rack setup (similar to the ACU), a modem AC power rack and modems, an RF and pressure mounting shelf, a circuit breaker module rack, DC power supplies (often the more rugged versions from the DCP), a power reset assembly, a Faraday box for electromagnetic interference protection, and heaters for climate control. Modern SCAs also often feature upgraded internal communication to Ethernet-based systems and larger, solid-state hard drives in a mirrored (RAID) configuration for data redundancy and improved performance.

In essence, the SCA represents a more modern, streamlined, and efficient approach to deploying ASOS, providing the same critical weather data collection capabilities in a more integrated and manageable package.