Answer:
When vacuum tubes were invented in 1890, the electronic computer era started. Compared to prior electromechanical devices, these tubes were thousands of times quicker. The Attansoff-Berry Computer was its name (ABC computer). Instead of electromechanical relays, the ABC computer employed vacuum tubes (an electrical device). When vacuum tubes were invented in 1890, the electronic computer era started.
Explanation:
An electromechanics professional (as myself) had studied a number of general courses about electronics, electricity and mechanics, in order to deal with integrated systems such as industrial robots, wind turbines, 3D printers and even the elevators of your building. All these systems rely on digital controls (sensors, processors, actuators, display panels) but are not purely digital, as they involve movement of small and big objects, and the use of significant amounts of energy in different forms (electricity, hydraulic force, electro-magnetism, etc.)
While an electromechanics engineer can design, build, operate and maintain such complex systems, it might not be able to design their individual components, such as an LCD display, a jet turbine or a power transformer, which indeed require a specialized electronics, mechanics or electric engineer respectively, do to so.
On the other hand, the electronics professional lives in 2 dimensions, one is that of the objects that leash and manipulate the electrons to detect, process and transmit digital signals, using semi-conductors to obtain physical items like a transistor, a LED light and a computer CPU; another dimension is the logical and digital world of software, where the 1s and 0s already captured by the physical devices are effectively used to do things as command the elevators to come to the eight floor as well as to send and email.
So, in essence, electromechanics is a more general field dedicated to the integration of digital and physical systems, and electronics is a more focused field dedicated to manipulate electrons and give life to the digital world.