These articles discuss various methods for digital communications with measuring instruments and test equipment.
USB Interface Basics provides an overview of the Universal Serial Bus and how it is used with test & measurement instrumentation.
Introduction to RS-232 Devices reviews this serial communication standard and compatible instrumentation.
RS-485 Communication Overview discusses the RS-485 standard for asynchronous serial communication using differential signal lines shared by up to 32 devices.
Bluetooth for Instrumentation describes the Bluetooth communication interface and shows some of the instrumentation products with this capability.