Console

Console is the terminal used by the operator to communicate directly with the CPU. The console terminal is the only terminal that can communicate directly with the microprogram. (See also OPCOM). The terminal with the lowest device number (normally Teletype 1 / Display 1) is the console. This terminal is different from others in three respects:
 * 1) error messages from RT programs and SINTRAN are always printed on Terminal 1. (Optionally, this may be altered to another terminal)
 * 2) when the computer is in STOP mode, the built in microprogram can only be reached from this terminal.
 * 3) when the command @SET-UNAVAILABLE is given, it is impossible to log in from terminals other than Terminal 1. This condition may be reset by the command @SET-AVAILABLE. Both commands are restricted to user SYSTEM.

Reference

 * , from Glossary
 * , section 6.1, fifth paragraph