3. Universal Interfaces

Standardized interfaces are everywhere. For USB (Universal Serial Bus) there has been an evolution in both the physical connector standard (and the connector is an interface right?) as well as the electrical and signaling protocol (USB-1/2/3). But these interfaces are indeed universal and they are standardized. If a USB thumb drive says USB-3, and your computer supports USB-3 then you expect to be able to use that thumb drive.

Observatories

In an observatory, the main interfaces are between the computer programs (apps) that use devices and the devices themselves. Usually the device is modular itself, with adapter software on the computer (a driver) and the separate physical device hardware (e.g. mount).

The two device modules communicate any way they want. The adapter provides a standardized interface to make the device look the same to all apps as all other devices of that type. in the above diagram the Driver-Client Interface points to the common interface on the app and on the adapter/driver. Note that the "device" in the diagram includes both the physical hardware and the adapter/driver. They form a unit consisting of two modules and some private interface between them.

If you're still a bit blurry about interfaces, go back to 1. Overview of ASCOM and re-run the little flip chart presentation. See if you can identify where the interfaces are in each modular diagram. (hint: look for the horizontal lines). If you have the concept now, please continue onward to 4. ASCOM Basics