It looks like an IBM 5285 or 5281 (they both look identical unless you can see the model number under the IBM logo on the front). The basic difference between the two is that the 5285 is a stand alone programmable unit and the 5281 had to be connected to a 5285 or 5288 in order to work. They were part of the IBM 5280 series of Distributed Processing Systems. Essentially, they were used for data entry (key to an 8" floppy disk) and could function as a batch RJE (Remote Job Entry) to an IBM mainframe via modem through a dial-up or dedicated line. Its programming abilities allowed you to perform data validation before transmitting it to the mainframe, thus saving time and improving data quality. The 24x80 display screen permitted the data to be formatted, making it easy to read. This was a tremendous improvement from key punch days where the printing was over the card column and you had to know where the fields started and ended.
The 5285 appeared sometime around 1980. I was trained on the machine at an IBM school in October of 1980. As I recall, the 5285 had a maximum memory of 64K and the 8" floppy disk had a capacity of about 1MB. A 10MB hard drive (which replaced one of the floppy drives) appeared on the scene later. Initially, programming was accomplished using DE/RPG (Data Entry/Report Program Generator). A COBOL compiler was offered later. The COBOL compiler was unique. It was too large to run on the 5285 so you compiled the COBOL source code on an IBM mainframe which generated 5280 object code that you downloaded and saved to the 5285 ( or 5288 ) for execution.
We used 5285s for payroll and accounting applications at coal mines in Pennsylvania and West Virginia. They were reliable and required no special environmentals. This was important as mine offices tend to accumulate a lot of dirt and dust.