The ANSI standard attempted to address these problems by making a command set that all terminals would use and requiring all numeric information to be transmitted as ASCII numbers. In addition, many of these terminals required sending numbers (such as row and column) as the binary values of the characters for some programming languages, and for systems that did not use ASCII internally, it was often difficult to turn a number into the correct character. While the two terminals had identical functionality in this regard, different control sequences had to be used to invoke them.Īs these sequences were different for different terminals, elaborate libraries such as termcap ('terminal capabilities') and utilities such as tput had to be created so programs could use the same API to work with any terminal. The Hazeltine 1500 had a similar feature, invoked using ~, DC1 and then the X and Y positions separated with a comma. One example is the VT52 terminal, which allowed the cursor to be placed at an x,y location on the screen by sending the ESC character, a Y character, and then two characters representing with numerical values equal to the x,y location plus 32 (thus starting at the ASCII space character and avoiding the control characters). 3.5 OSC (Operating System Command) sequencesĪlmost all manufacturers of video terminals added vendor-specific escape sequences to perform operations such as placing the cursor at arbitrary positions on the screen.3.4 SGR (Select Graphic Rendition) parameters.3.3 CSI (Control Sequence Introducer) sequences.

Vt100 escape sequences