HP 3000 Manuals HP 3000 Manuals
Shift-out/Shift-in Control Character Handling The shift-out/shift-in (SO/SI) control charactersare handled slightly differently between the Asian HP terminal and the IBM Asian display station. They are not used to enable and disable the DBCS characters on HP terminals. Here is a description of the differences when a user is inputting data and when data is displayed on the user's terminal. Differences During User Input of Data Unlike the IBM PS/55 display station, HP terminals do not update the screen with SO and SI control characters when the user types DBCS data. Pass Thru does not process the DBCS data until the user presses the ENTER key, because Pass Thru uses HP "block mode" terminal protocol, where the terminal does not interrupt the HP 3000 after each character is typed. Pass Thru inserts SO and SI control characters around the DBCS characters and performs DBCS syntax checking of all the DBCS fields on the screen. If a field is already full, and Pass Thru attempts to insert SO and SI control characters around the DBCS characters, data overflow may occur, because Pass Thru has no room to insert the additional SO and SI control characters. Pass Thru will truncate data at the end of the field to make room for the SO and SI characters. A warning message will be sent to the user's terminal and will appear at the bottom of the screen. Differences on User's Terminal Screen Instead of displaying the SO and SI control characters directly on the HP terminal, Pass Thru will map the SO and SI characters to a single-byte blank and display them as blanks on the HP terminal screen.