IBM 5250 is a family of block-oriented terminals originally introduced with the IBM System/34 midrange computer systems in 1977. It also connects to the later System/36, System/38, and IBM AS/400 systems, and to IBM Power Systems systems running IBM i. Components 5250 devices can be directly attached to the host or communicate remotely using Synchronous Data Link Control (SDLC) at up to 9600bit/s. Devices can also be clustered or daisy-chained. In 1980 the 5250 system consisted of the following components: 5251 Display Station. The monochrome text-only display can be either 960 characters, formatted as 12 lines of 80 characters, or 1920 characters as 24 lines of 80 characters. Upper and lower case is standard. Text attributes consist of blink, high intensity, reverse video, non-display, underscore, and a unique column separator that causes the field to be preceded and followed by a vertical bar. 5251 and 5252 input format control attributes are optimized for data entry applications and offer significant enhancements over previous 3270 terminals. 5252 Dual Display Station. The 5252 features a single CRT displayed 12 lines each on two different sides back to back in a single case, with separate keyboards. The 5252 was not part of the initial announcement. 5256 printer. The 5256 is a tabletop serial dot matrix printer with three models providing speeds of 40, 60, or 120cps and a print line of 132 characters. 5251/5252 format control Field attributes also define the type of data the operator can enter into a field, and specify other control information for the field. A field can be defined as alpha only, numeric only, or alphanumeric. Auto enter simulates an ENTER key press at the conclusion of the field. Bypass automatically skips over a field in the screen. Duplicate enable allows the operator to press the DUP key in a field, entering a special code which is interpreted by the application program – typically duplicating data in this field from the previous record or line. Field exit required forces the operator to manually exit this field, rather than automatically advancing to the next field after entering the last character. Mandatory entry specifies that the operator must enter data in this field and is not allowed to tab over it. Monocase translates lower-case characters entered into this field to upper-case. Mandatory fill specifies that this field must be entirely filled if any data is entered into it. Right adjust will