Teleprinter Input-Output Test

This document describes a diagnostic program designed to test the input and output functions of a teleprinter (Models 33KSR or 28KSR) connected to a PDP-7 computer. The program includes four main tests:

1. Repeating Single Character Output: Outputs a single character repeatedly on a line.
2. Repeating Character Sequence Output: Outputs a predefined sequence of alphabets, digits, and symbols, repeating the sequence.
3. Input Line, then Output Same Line: Allows the user to type a message line, which is then output by the teleprinter.
4. Input Character, then Output Same Character (Echo): The teleprinter immediately echoes each character typed by the user.
5. Repeat Input Sequence: A typed sequence is repeated once after a carriage return, with options to re-trigger.

The program is loaded via the RIM loader from a Teleprinter Test tape and starts automatically at memory location 20 (octal). AC switches on the computer allow control over features such as variable time delays between output characters and specifying characters for certain tests. The program occupies 20-1000 memory locations and handles tape formats including ASCII, FIO, DEC, and FB.