Terminals That Can Be Used with Pass Thru

• Security Video

• Shifted Function Keys

• Softkey Label Display

• Auto Keyboard Lock and Send Cursor Position

• Modified Data Tags

Pass Thru supports security video for non-display input fields on certain HP terminals. With security video, data typed in a non-display field is not displayed on the screen. The "Security Video" column in Tables C-1, C-2, C-3, and C-4 indicates whether a terminal supports security video. See "Non-Display Input Fields," in Chapter 5 “Using Terminals with Pass Thru”, for more information on security video.

HP terminals have 8 function keys. Some HP terminals allow you to use the [SHIFT] key to create uppercase and lowercase function keys, giving you 16 instead of 8. The "Number of Function Keys," column in Tables C-1, C-2, C-3, and C-4 indicates the number of function keys a terminal supports (8 or 16).

Some HP terminals will display softkey labels in windows on the screen, to tell you which softkey functions your function keys have at the current level. These softkey labels have defaults, or you can configure them in the PTCONFIG file (see Chapter 2 “Configuring Pass Thru”) The "Softkey Label Display" column in Tables C-1, C-2, C-3, and C-4 indicates whether a terminal will display softkey labels on the screen.

Some HP terminals have a feature called Auto Keyboard Lock. When you press the [ENTER] key on one of these terminals to transmit data, the keyboard is automatically locked until a response is received from the IBM host. Then, the HP 3000 sends an instruction to the terminal that unlocks the keyboard. Terminals with the Auto Keyboard Lock feature also have a feature called Send Cursor Position. When data is transmitted from these terminals, the exact cursor position is sent with the data, telling the IBM host where the cursor was when the keyboard was locked. The "Auto Keyboard Lock/Send Cursor Position" column in Tables C-1, C-2, C-3, and C-4 indicates whether a terminal supports the Auto Keyboard Lock and Send Cursor Address features.

When using Pass Thru, you should keep in mind the differences between a terminal with the Modified Data Tag (MDT) feature and a non-MDT terminal.

An MDT terminal transmits all changed data fields, including data fields that are overwritten by identical data. A non-MDT terminal transmits only those fields that are different from the internal screen image, which contains the data last written to the terminal by Pass Thru. Fields on a non-MDT terminal that have been overwritten with identical data are not sent to the host, because the data does not differ from the data in the internal screen image.

When the IBM host sends null characters, the nulls are translated to blanks for your HP terminal. If you are using a non-MDT terminal, and you type some blanks into a field that previously contained nulls, the HP 3000 compares the data from your terminal with the internal screen image and finds no difference. The data appears to be unchanged, so the HP 3000 transmits no data to the IBM host.

	NOTE: If you are currently using non-MDT terminals, you should consider upgrading to MDT terminals. MDT terminals will transmit blanks that have been typed over nulls. They will also improve performance, because data from the terminal does not have to be compared with the internal screen image before it can be sent to the host. If you are using an HP 700/94 terminal, a ROM module (part #5062-1306) is now available that allows it to support null characters just like an IBM 3278 display station.

In Tables C-1, C-2, and C-3, the "MDT/Non-MDT" column indicates whether a terminal supports the Modified Data Tag (MDT) feature. Currently, all HP Asian terminals and PCs function as non-MDT terminals.