VT52 commands normally consisted of the escape character and a single character following it. The exception to this rule was the Y command, which also required two numbers to be sent, representing the X and Y coordinates of the cursor position, with the upper left corner of the screen being position 1,1. These numbers were sent as ASCII characters of that value, adding 31. For instance, to position the cursor at column 30 and line 20, you would add 31 to each value to get 61 and 51, then look up those ASCII characters, and . The complete command would then be (note the row,column ordering, not X, Y). Adding 31 ensures that the characters are shifted out of the control range into the printable character range, so they will transmit properly on 7-bit links.