Visual communication is a large umbrella that is used to describe many areas of communications. It is a term used to describe ideas and information that can be read or looked at and a similar understanding or response is gained. It applies to signage, typography, drawing, illustration and graphic design--all of which rely on vision as their key similarity.
The history of visual communications can arguably be dated back 40,000 years ago with the first known markings on cave walls. These cave paintings were used to communicate, in one case, as a pictograph to document an object, and in another case, as an ideograph where the images are used to communicate an idea rather than the object itself. Through the progress of trade and the invention of paper came documentation and the invention of the alphabet used in manuscripts. In the 1500s came the invention of the printing press and the first printed book. Visual communication has progressed all the way through to modern day technology and the computer where it is heavily used on the Internet. Almost every object you touch or piece of technology you use has some degree of visual communication associated with it.
Visual communications is basically communication that happens visually. Another explanation of visual communications is communications that incorporates type and image. In either case, it is communications that is used to communicate an idea to the viewer.
While technology is making it easier for anyone to take on a bit of graphic design or visual communications himself, you have to wonder if in the end it is a good idea. We are finding nephews who are designing company web pages and mothers who are designing signage and brochures for their husbands' companies. Because they have a computer and a few software packages, they consider themselves professionals. This is not the case. In the end, the business will find those products were not successful in gaining them new business.
There are all levels of professionals in the field of design and visual communications. You may want to check out their credentials. While there is no licensing for these professionals, you can check their resumes for college degrees at the level of Associate's degree, Bachelor’s degree, Bachelor of Art Degree (a bit more focused) or a Master's degree. While a degree is not required, if none is listed, you may want to check associations they belong too or awards they have earned. All will tally up to the level of quality you desire when hiring a professional.
Visual communications closely relates to the following fields: advertising, visual culture, graphic design, art directing, illustration, communication and typography. Practical applications of visual communication could be in the medical field, music industry or science labs with imaging and charting and mapping. Businesses would use flow, information and data visualization. Different fields of technology would use visual communications such as software visualization.