Terminals and Printers Handbook 1983-84

Chapter 4

VT200 Family User Information

This keyboard is used by all members of the VT200 family.

Controls and Indicators

VT200 family terminals perform two functions. First, they act as an input device to the computer, helping you to enter information that is sent to the computer. Second, they simultaneously act as an output device for the computer, displaying data on the video screen. This section describes the controls and indicators found in the VT200 family of terminals.

Figure 4-2 VT240 Series “Power OK” Indicator

Monitor Controls and Indicators

Figure 4-3 Monitor Brightness, Contrast, and Tilt Controls

The table below describes the monitor controls and indicators for the VT220 and VT240 Series video terminals.

Table 4-1 VT200 Family Controls and Indicators
Terminal	Indicator/Control	Description
VT220, VT240*, VT241	Power OK Indicator	Lights up to indicate that power is on.
VT220, VT240, VT241	Voltage Selector Switch	Enables the terminal to operate on 120 Vac or 240 Vac.
VT220, VT240, VT241	Power Switch	Turns power to the terminal on and off. On the VT241 terminal, there is a power switch on both the monitor and the system box.
VT220, VT240, VT241	Contrast Control	Adjusts the contrast of the display screen.
VT220, VT240, VT241	Brightness Control	Adjusts the brightness of the display screen.
VT220 and VT240 only	Tilt Mechanism Button	Located on the bottom of the monitor. Used to adjust the angle of the monitor by raising or lowering the rear of the monitor.
* These two controls and one indicator are located on the System Box.

Keyboard Controls and Indicators

The VT200 family keyboard consists of a main keypad, an editing keypad, an auxiliary keypad, a row of special function keys, four visual indicators, and two audible indicators.

Figure 4-4 Austrian/German VT200 Family Keyboard

Main Keypad

The main keypad operates similar to that of a standard typewriter keyboard. When you press a letter, numeral, or symbol key, the character is sent to the host’s memory and is displayed on the screen. Uppercase letters and symbols are generated when you press the SHIFT or LOCK keys.

Figure 4-5 VT200 Family Main Keypad

Table 4-2 Main Keypad Function Keys
Key	Description
Tab	Generates a horizontal tab that normally moves the cursor and the text following it to the next tab stop setting.
CTRL	When pressed in combination with another key, the CTRL key causes the terminal to transmit a code that has a special meaning to your system.
Lock	When pressed, the LOCK key makes the alphabetic keys generate uppercase characters. When the LOCK key is pressed again, the alphabetic keys generate lowercase characters.
Shift (2 keys)	When either the right or left side SHIFT key is pressed, the uppercase function of all keys is enabled. If a key does not have an uppercase function, the SHIFT key will be disregarded. In some cases, this key is used in combination with another key to generate a predefined control function.
Return	Transmits either a carriage return (CR) code or a carriage return (CR) and linefeed (LF) code. In some cases, it moves the cursor to the next line when editing text. If NEW LINE was selected in Set-Up mode, RETURN can be a signal to the applications program that a particular operation is finished.
Delete	Pressing this key generates a DEL character. Normally, this erases one character to the left of the cursor.
Compose Character	This key is used to create special characters, such as , , and , that do not exist as standard keys on your keyboard. Use of this key and compose character sequences are described in detail in the VT220 and VT240 Owner’s Manual.

Figure 4-6 VT200 Family Editing Keypad

Editing Keypad

The editing keypad consists of four cursor (arrow) keys and six keys directly above them. (See Figure 4-6.) The four arrow keys move the cursor in the direction indicated by the arrow. The six editing keys have functions assigned to them by the applications software in use. See your applications software documentation for details.

Auxiliary Keypad

This keypad is used to enter numeric data as you would with a standard calculator. In addition, you can assign functions to these keys to be used by the applications software. Again, see your applications software documentation for details.

In some applications, the ENTER key generates either a carriage return or a carriage return and a linefeed. It is also used in Set-Up to select terminal operating characteristics.

Special Function Keys

Most of the top-row function keys have functions assigned to them by the software in use. Those keys with Digital-defined functions are listed below.

Table 4-3 Special Function Keys
Key	Description
HOLD SCREEN	This key freezes the screen display and stops new characters from being displayed. To “unfreeze” the screen display, just press the key again.
PRINT SCREEN	Pressing this key alone stops all screen activity and sends screen text display to the printer. Holding down SHIFT and PRINT SCREEN simultaneously stops all screen activity and sends the screen display to the printer. Holding down CTRL and PRINT SCREEN sets or resets the Auto Print Mode.
SET-UP	Pressing this key causes the terminal to go into Set-Up mode. Pressing it while the terminal is in set-up returns the terminal to either the on-line or local mode, wherever it was before you entered set-up mode.
DATA/TALK	This key functions only if the integral modem option is installed. It sets the modem to data, talk, or dialer mode. See the VT240 Series Owner’s Manual for details.
BREAK	The BREAK key is used to send a break signal. The SHIFT and BREAK keys initiate a disconnect and is the recommended way to disconnect the terminal from the communications line. See the VT220 or VT240 Series Owner’s Manual for details.
F11 (ESC)	F11 is normally a function key used by application programs. In VT100 and VT52 modes, it generates an ESC (escape code) character.
F12 (BS)	F12 is normally a function key used by application programs. In VT100 and VT52 modes, it generates a BS (backspace) character.
F13 (LF)	F13 is normally a function key used by application programs. In VT100 and VT52 modes, it generates an LF (linefeed) code.

Figure 4-7 VT200 Family Special Function Keys

Visual Indicators

The keyboard has four visual indicators.

Hold screen: This indicator lights up when the HOLD SCREEN key is pressed. To resume text scrolling, press the HOLD SCREEN key again.
Lock: This indicator is lit when the LOCK key has been pressed. It indicates that the terminal will generate uppercase characters only.
Compose: This light is on during a “compose sequence” and is initiated by pressing the COMPOSE key. The light goes out upon the completion of the compose sequence.
Wait: This light is on when the keyboard is locked, preventing transmission of information because its buffer is full. Once the information in the buffer is accepted by the host, the WAIT light goes out and transmission resume. Sometimes, the host “locks” the keyboard.

Audible Indicators

The terminal generates a bell tone as part of the power-up self-test. In Set-Up you can enable or disable the margin bell tone, which sounds when the cursor reaches the right-hand margin, and/or a warning bell tone to indicate operator errors.

You can also enable or disable the keyclick sound when in Set-Up mode. This lets you know that the key has been pressed fully. Exceptions to this are pressing SHIFT or CTRL only, and typing when the keyboard is locked.

Operator Features

The VT200 family stores many of its operating characteristics in a nonvolatile memory that retains these settings even when the power is shut off. These operating characteristics can be changed by entering the Set-Up mode. Some characteristics, such as transmit and receive speed, affect communications with the host and printer. These must be set according to the host’s and printer’s requirements. Other characteristics, such as the type of cursor to be displayed, can be set according to your preference. Through the keyboard or the host, you can change all the available Set-Up characteristics to tailor the terminal to your preference.

Set-Up

Set-Up is based on selectable monitor displays called “screens”. Only one screen can be displayed at a time. Each one presents a logical grouping of choices from which you can select terminal parameters.

You can even enter Set-Up while you are working in a file without loss of data. The data is redisplayed when you exit Set-Up. Entering Set-Up is achieved by pressing the Set-Up key. The Set-Up Directory screen is displayed immediately. This screen lets you access any other Set-Up screen. It also presents fields you can access to select terminal operating parameters. To select a field, use the arrow keys to position the cursor at the field you want to invoke. Then use the ENTER key to invoke the field.

Set-Up Screens

Each screen contains:

Screen title: Blinks and identifies the current screen.
Terminal identifier: Identifies if the terminal is VT220 or VT240.
Firmware version number: Identifies the level of terminal firmware.
Action fields: These are choices that offer a single value. When you select and invoke an action field, a single action is performed. For example, each screen, except the Set-Up Directory screen, has an action field that reads “TO DIRECTORY.” Invoking this field replaces the current screen with the Directory screen.
Parameter fields (not found on all screens): These are blocks of self-describing text that offer more than one choice. When you select a parameter field, the field offers you a range of choices. For example, if you select the TRANSMIT SPEED parameter field, you can then choose from one of the following speeds: 75, 100, 150, 300, 600, 1200, 2400, 4800, 9600, and 19,200 baud. Each parameter field has a factory default value that is invoked if you do not change it. The value currently in a field is the value that will be invoked when you exit Set-Up.
Text parameter fields (not found on all screens): These are fields that require you to make a direct text entry through the keyboard. If you select one of these, the screen prompts you for text input, such as the answerback message.
Status line: This appears at the bottom of the Set-Up screen. This line is merely a reporting line that gives you a status report on the modem’s state, the printer, and the terminal insert/replace mode. See the VT220 and VT240 Series Owner’s Manual for more detail.

During set-up the ENTER key can also do the following:

When the cursor is positioned on an action field, the ENTER key invokes the described action.
If the cursor is on a parameter list, the field value displayed is changed when you press ENTER. You can use ENTER to toggle through the possible field values. The value you leave displayed is the value invoked.
When you press ENTER and the cursor is on a text parameter field, the terminal prompts you for text.
You can also use the ENTER key to toggle through the sequence of Set-Up Screens – General, Display, Keyboard, Communications, Printer, and Tab, plus Graphics and Telephone for the VT240 Series.

Set-Up Directory Screen

This is the first of the screens displayed in set-up mode. The Set-Up Directory screen enables you to move through the sequence of Set-Up screens – display, general, communications, printer, keyboard, tab, graphics (VT240 Series only), and Telephone (VT220 and VT240).

It also lets you select the following:

Table 4-5 Set-Up Directory Screen Features
Field and Field Type	Default	Functions
Graphics (VT240 Series only) Action	None	Replaces the Set-Up Directory Screen with the Graphics Set-Up Screen.
On Line Parameter	On-line	Selects on-line or local operation.
Clear Display Action	None	Clears the text on the display that becomes visible when Set-Up is exited.
Clear Comm Action	None	Clears communications by: aborting print operation, escape or control sequence, or device control string processing; clearing keyboard buffers; putting terminal on-line; and sending XON to the host port, if XOFF support is enabled.
Reset Terminal Action	None	Sets many terminal features to a known state. See VT220 or VT240 Series Owner’s Manuals.
Recall Action	None	Replaces all current Set-Up parameters with “saved” values and clears the monitor screen.
Save Action	None	Saves all parameters from the Set-Up screens.
Set-Up = Parameter	None	Selects the language (English, French, or German) in which you want the Set-Up screens displayed.
Keyboard Parameter	None	Selects correct terminal operation for the national keyboard (North American, British, Flemish, Canadian French, Danish, Finnish, German/Austrian, Dutch, Italian, Swiss French, Swiss German, Swedish, Norwegian, French/Belgium, or Spanish) you are using.
Default Action	None	Replaces all current Set-Up parameters with factory default settings and clears the monitor screen.
Exit Action	None	Exits Set-Up and returns the terminal to the operating mode, local or on-line, that was selected in Set-Up.

Display Set-Up Screen

The Display Set-Up screen lets you define monitor display characteristics.

Table 4-6 Display Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Action	None	Replaces Display Set-Up screen with General Set-Up screen.
To Directory Action	None	Replaces Display Set-Up screen with Set-Up Directory screen.
__ Columns Parameter	80 columns	Lets you select 80 or 132 column display.
__ Controls Parameter	Interpret Controls	Lets you select whether control function codes from the host are displayed as characters and not executed or interpreted as controls and not displayed as characters.
Auto Wrap Parameter	Auto Wrap	Selects whether a received character after the right margin is automatically displayed in the first character position on the next line, or overwritten into the last character position on the correct line.
Scroll Parameter	Smooth Scroll	Select the method which lines on the screen scroll up or down. Your choices are smooth, jump, or no scroll.
Text, Screen Parameter	Light text, dark screen	Lets you select a dark screen with light text or a light screen with dark text.
Display (VT240 only) Parameter	Monochrome Display	Selects the color map to operate with monochrome or color monitor, or both (when using both monochrome and color monitors). Note: Color display is available only when you have the color monitor option for the VT240.
Text Cursor Parameter	Cursor	Lets you select whether or not a cursor is displayed in text mode.
Cursor Style Parameter	Block Style	Lets you select block or underline cursor style.

General Set-Up Screen

The General Set-Up screen lets you define a group of general operating characteristics.

Table 4-7 General Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Action	None	Replaces General Set-Up screen with Communications Set-Up screen.
To Directory Action	None	Replaces General Set-Up screen with Set-Up Directory screen.
Mode Parameter	VT220 mode, 7-bit controls	Selects the basic terminal operating mode: VT220 mode, 7-bit controls; VT200 mode, 8-bit controls; VT100 mode; VT52 mode, and; 4010/4014 mode (VT240 Series only).
VT100 Parameter	VT100 ASCII	Selects the default character set used in the VT100 or VT52 mode. (ASCII or U.K. characters).
User Defined Keys Parameter	Locked	Lets you select whether or not the host can alter User Defined Key definitions.
User Features Parameter	Locked	Lets you select whether or not the host can alter user-preference features you have set, such as auto repeat, scroll, and screen.
Keypad Parameter	Numeric keypad	Selects whether the keypad transmits ASCII character codes or control codes, used by applications software.
New Line Parameter	No New Line	Lets you select whether the RETURN key generates a carriage return only or a carriage return and a line feed.
Cursor Keys Parameter	Normal Cursor Keys	Normally selected by the host computer. Selects whether the cursor keys transmit ANSI cursor control sequences or application control function.

Communications Set-Up Screen

The Communications Set-Up screen lets you define the terminal-host communications environment.

Table 4-8 Communications Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Action	None	Replaces Communications Set-Up screen with Printer Set-Up screen.
To Directory Action	None	Replaces Communications Set-Up screen with Set-Up Directory screen.
Transmit = Parameter	4800	Lets you select the rate (75, 110, 150, 300, 600, 1200, 2400, 4800, 9600, or 19,200 bits per second) at which the terminal sends data to the field host computer. Terminal transmit speed must equal the computer’s receive speed.
Receive = Parameter	4800	Lets you select the rate (75, 110, 150, 300, 600, 1200, 2400, 4800, 9600, or 19,200 bits per second) at which the terminal receives data from host computer. This must equal the computer’s transmit speed. The terminal, however, can send at one speed and receive at another.
XOFF Parameter	XOFF at 64	Lets you select the XOFF point or disable the automatic XON/XOFF flow control. Other choices include no XOFF and XOFF at other speeds. VT240 Series values differ from those of the VT220. See VT220 or VT240 Series Owner’s Manuals and VT220 or VT240 Series Programmer’s Reference Manuals for details.
Bits, Parity Parameter	8 bits, no parity	Lets you select the serial character communication format used for communication with the host computer. For other choices, see your VT220 or VT240 Series Owner’s Manuals. This does not set the format for communication with a printer.
Stop Bit Parameter	1 Stop Bit	Lets you select the number of stop bits (1 or 2) used by the host port. This does not set the bits for the printer port.
Local Echo Parameter	No Local Echo	Lets you enable or disable local echo.
Port Parameter	EIA port, Data Leads only	Lets you select the type of port used to communicate with the host. Your choices include: 20 mA port, EIA port with data leads only, EIA port with modem controls, or integral modem (VT240 Series only). See VT220 or VT240 Series Owner’s Manuals and VT220 or VT240 Series Programmer’s Reference Manuals for details.
Disconnect, Delay Parameter	Disconnect, 2 s delay (For all countries except the United Kingdom, which uses 60 ms.)	Lets you enable or disable the disconnect feature and, when modem controls are used, to set the time between when the received line signal drops and disconnection.
Transmit Parameter	Transmit	Lets you limit the terminal transmit speed to between 150 and 180 characters per second, regardless of baud rate.

Printer Set-Up Screen

The Printer Set-Up Screen lets you define printer operations.

Table 4-9 Printer Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Action	None	Replaces Printer Set-Up Screen with Keyboard Set-Up Screen.
To Directory Action	None	Replaces Printer Set-Up Screen with Set-Up Directory Screen.
Speed = Parameter	9600	Selects the rate (75, 100, 150, 300, 600, 1200, 2400, 4800, 9600, and 19,200) at which the terminal sends data to the printer or auxiliary device.
Printer to Host (VT240 Series only) Parameter	No Printer to Host	Selects whether or not input from the printer or auxiliary device is sent to the host computer.
Mode Parameter	Normal Print Mode	Selects the operating mode – normal, auto print, or controller – for the printer.
Bits, Parity Parameter	8 bits, no parity	Lets you select the character format of the characters used at the terminal printer port. See the VT220 or VT240 Owner’s Manual for details.
Stop Bits Parameter	1 Stop Bit	Sets the number of stop bits (1 or 2) to match those used by the printer or auxiliary device.
Print Parameter	Print Full Page	Lets you select how much of the screen (the full screen or just the scrolling region) is to be printed during a print operation.
Printed Data Type Parameter	ASCII or UK only	Selects the type of characters (from the terminal’s character sets) to the printer. Choose from ASCII or UK only, ASCII or UK line drawing, or all characters. (Only for devices which support Digital’s multinational character set.)
Term Parameter	No Terminator	The print terminator field lets you select what characters come at the end of a print page operation. Selecting Term = FF ends the print page operation with a carriage return, line feed, and form feed. Selecting No Term ends the print page operation with a carriage return and linefeed.

Keyboard Set-Up Screen

The Keyboard Set-Up Screen lets you define operating characteristics associated with the keyboard.

Table 4-10 Keyboard Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Action	None	Replaces Keyboard Set-Up Screen with Tab Set-Up Screen.
To Directory Action	None	Replaces Keyboard Set-Up Screen with Set-Up Directory Screen.
Keys Parameter	Typewriting Keys	Lets you select the appropriate keyboard map for the physical keyboard, either typewriter or data processing. See
Lock Parameter	Caps Lock	Lets you select the way in which the SHIFT and LOCK keys operate.
Auto Repeat Parameter	Auto Repeat	Lets you select whether or not keystrokes are automatically repeated when you hold down a key.
Keyclick Parameter	Keyclick	Lets you select whether or not the keyboard generates a click sound each time a key is pressed.
Margin Bell Parameter	Margin Bell	Lets you select whether or not the terminal generates a bell tone when the text cursor reaches the right-hand margin.
Warning Bell Parameter	Warning Bell	Lets you select whether or not the terminal generates a bell tone on receipt of CTRL G or operating errors.
Break Parameter	Break	Lets you enable or disable the Break function.
Auto Answerback Parameter	No Auto Answerback	Lets you select whether or not the answerback message is automatically transmitted to the host after a communication line connection.
Answerback Text Parameter	None	Provides for user-defined answerback message entry.
Concealed Parameter	Not Concealed	Lets you select whether or not your answerback message is displayable on the Set-Up screen.

Tab Set-Up Screen

The Tab Set-Up Screen lets you set terminal tab stop setting. Beneath the tab stop fields is a ruler which you can reference when setting tabs. Each tab stop field can show a “T” (tab stop setting) or can be blank (no tab stop setting). You control the tab stop field cursor using the arrow keys. Pressing the ENTER key after you select a field places a “T” in a blank field or removes an existing “T”.

Table 4-11 Tab Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Action	None	Replaces Tab Set-Up Screen with Display Set-Up Screen (VT220) or Graphics Screen (VT240 Series).
To Directory Action	None	Replaces Tab Set-Up Screen with Set-Up Directory Screen.
Clear All Tabs Action	None	Clears all previously set tabs.
Set 8 Column Tabs Action	None	Automatically sets tabs every 8 columns starting with column 9.

Graphics Set-Up Screen

The VT240 Series only Graphics Set-Up Screen lets you define graphics parameters for use by your VT240 Series terminal. To set the Tektronix 4010/4014 parameters, refer to the documentation for the applications software you are using.

Table 4-12 Graphics Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Action	None	Replaces Graphics Set-Up Screen with Display Set-Up Screen or Telephone Set-Up Screen if optional modem is installed.
To Directory Action	None	Replaces Graphics Set-Up Screen with Set-Up Directory Screen.
Graphics Cursor Parameter	Graphics Cursor	Lets you select whether or not the graphics cursor is displayed in graphics mode.
Macrograph Report Parameter	No Macrograph Report	Lets you select whether or not the contents of a macrograph report is sent in response to the ReGIS Report Macrograph Command.
4010 CR Effect = Parameter	None	Lets you select whether a received carriage return generates a carriage return only or a carriage return and a linefeed.
4010 LF Effect Parameter	None	Lets you select whether a received linefeed generates a linefeed only or a linefeed and carriage return.
Graphics Print Parameter	Compact Graphics	Lets you select the size of the image on the graphics printer. Invoking compact graphics produces an image that is approximately three-by-five inches. Invoking the expanded graphics choice produces an image that is approximately seven-by-nine inches.
4010 DEL = IMPLIES Parameter	None	Lets you enable or disable the 4010/4014 “DEL IMPLIES Lo Y” strap option.
GIN Terminator = Parameter	None	Lets you select the characters that follow graphics input (GIN) address transmission – carriage return, carriage return and end of transmission, or no character.

Telephone Set-Up Screen (VT240 Series Only)

The Telephone Set-Up Screen is available only if you have selected the optional modem for the VT240 Series terminal. This screen lets you store and display telephone numbers for automatic dialling.

Table 4-13 Telephone Set-Up Screen Features
Field and Field Type	Default	Functions
To Next Set-Up Screen Action	None	Replaces Telephone Set-Up Screen with Display Set-Up Screen.
To Directory Action	None	Replaces Telephone Set-Up Screen with Set-Up Directory Screen.
Manual Answer/Auto Answer Action	Manual	With manual answer, the VT240 terminal is in talk mode when disconnected or on power up. With auto answer selected, the terminal is in data mode when disconnected or on power up.
Telephone Number A = Text Parameter	None	Lets you enter a user-defined telephone number to be stored for dialing as designator A.
Telephone Number B = Text Parameter	None	Lets you enter a user-defined telephone number to be stored for dialing as designator B.
Concealed Parameter	Not Concealed	The screen has two Conceal fields. Each one “Conceals” or “Not Conceals” the telephone number entered at the left. Invoking Concealed causes the terminal to replace the telephone number with the text “concealed”. Invoking Not Concealed causes the terminal to display the telephone number as it is entered.

Communications

The VT220, VT240, and VT241 terminals communicate with a host and a printer via full-duplex, asynchronous lines only. There are 10 possible transmit/receive speeds that are selectable in Set-Up. Your VT220 and VT240 Series terminals operate in accordance with the following national and international communications standards and recommendations:

EIA Standard RS-232C
EIA Standard RS-423
CCITT Recommendation V.24
CCITT Recommendation V.26 (V.10)
CCITT Recommendation V.20 (V.21)

To communicate with the host, the VT220 and VT240 Series terminals use serial character format, which is selected in Set-Up. Digital recommends that the number of data bits be the same for the host port and the printer port. The stop and parity bits, however, can be selected separately for each port.

Host and Printer Port Interfaces

Members of the VT200 family have two asynchronous serial ports: one for communications with a host and another for communication with an auxiliary device such as a printer. The host port has two physical connectors. The EIA or COMM host port connector (EIA RS-232C) connects your terminal to a local or remote host. The 20 mA host port connects your terminal to a local host. The printer port, with a single physical connector (RS-232C/RS-423), connects your printer or another device to your video terminal. On the VT240 Series, the printer port operates as a serial input channel as well. Devices such as digitizers and tablets can be used to input data via this port.

Communications with a Host

The VT220 and VT240 Series can be directly connected to a local host computer or via telephone lines to a remote host computer. To communicate with a local host, use the 20 mA current loop connector or EIA host port connector using a null modem cable. Connection of the VT220 and VT240 Series to a remote host is made via telephone lines using a modem or acoustic coupler. The modem used at the video terminal end must be compatible with the modem used at the host computer end. The VT220 and VT240 Series accept compatible modems and acoustic couplers such as Bell 103, 113, and 212, including Digital’s DF02 and DF03 modems.

Communications with a Printer

You can locally connect your VT220 or VT240 Series terminal to an asynchronous serial printer using the appropriate cable. Digital’s current printers can be used with the VT220 terminal: LA50 Personal Printer, Letterprinter 100, LQP02 Letter-Quality Printer, DECwriter Correspondent, and DECprinter III. Even Digital’s traditional printers, the LA34, LA35, LA36, and LA38, can be used.

The printer port can be used as a serial input channel or input/output device (VT240 Series), as well as an output device. Choose the mode of operation you want in Set-Up. When the printer port is selected as an input device in Set-Up (Printer-to-Host Mode), data from the auxiliary device, as well as data from the terminal keyboard, can be sent to the host. Data from the printer port is treated the same as keyboard data.

If in Set-Up you select the printer port as an output device (No Printer-to-Host), text and graphics print functions can be initiated from the keyboard as well as from the host. In this mode, input from the printer is disabled.

When the printer port is selected in Set-Up as an input/output device (Printer Controller Mode), the device connected to the printer port is treated as the terminal, while the VT240 transparently monitors line traffic. This means all characters from the host are sent directly to the device connected to the printer port with the exception of XON, XOFF, NULL, and control functions from the host. These functions turn the Printer Controller on and off. All characters from the device are sent directly to the host with the exception of XON, XOFF, and NULL. There is a 256 character input buffer to support input from the printer port. See the VT220 and VT240 Series Owner’s Manuals for more details.

Figure 4-16 EIA and 20 mA Host Port Connectors

Printing Screen Display

When you VT220 or VT240 Series terminal is properly connected to an appropriate printer, you can locally print whatever is on the monitor screen. To print a monitor screen display that contains only text, press the keyboard PRINT key. This stops all screen actions and sends the information on the screen to the printer. To abort the printing process, just press the PRINT key again.

To print a monitor screen display that contains graphics (VT240 Series only), press SHIFT and PRINT simultaneously. Just as with printing only text, this action freezes the screen and sends all text and graphics information on the screen to the printer. If you want to stop the printing process, press SHIFT and PRINT together.

The VT220 and VT240 Series of terminals operate in one of four text print modes. These modes, selectable in Set-Up, are normal mode, auto print mode, printer controller mode, and local controller mode.

Auto Print Mode

Auto Print mode prints a hardcopy of the current text line before the cursor moves to the next line. The cursor moves to the next line when the terminal receives a linefeed, form feed, or vertical tab. When selected, auto print mode is indicated by a status line in Set-Up. After you have selected Auto Print in Set-Up, invoke the Auto Print mode by pressing the CTRL and PRINT SCREEN keys. To stop Auto Print Mode, press CTRL and PRINT keys again.

Normal Print Mode

Normal print mode lets you select all local printing functions through the keyboard.

Printer Controller Mode

Printer Controller Mode gives the host direct control of the printer. Characters received from the host go directly to the printer and are not displayed on the video screen. When invoked, Printer Controller Mode is indicated by a status line in Set-Up. This mode cannot be selected from the keyboard, except by entering Set-Up. Printer Controller Mode does not allow the use of local printing functions, for example, the PRINT SCREEN does not work.

Local Controller Mode

Local Controller Mode is selected by the local and printer controller Set-Up features in the Set-Up Directory. When these features are selected, Local Controller Mode supports keyboard output to the printer. This lets you set up various printers for operation, without involving the host.

Integral Modem/Auto Dialer (VT240 Series Only)

The integral modem/auto dialer functions are available if this option is installed. The integral modem/auto dialer function enables you to:

Allow a video terminal and a telephone to share the same telephone line, supporting both voice and data communications.
Use a telephone for normal voice communication.
Use the VT240 terminal keyboard to dial calls to a host instead of using the telephone as the dialing device.

Three modes of operation are available with the integral modem/auto dialer options:

Data Mode conditions the terminal for communicating data with the host.
Talk Mode lets you use the telephone for voice communication. Entering Talk Mode automatically aborts data communication with the host.
Dialer Mode lets you do three things. First, you can use the keyboard to type and store telephone numbers to be dialed automatically. Second, you can use a single keystroke to redial the last telephone number dialed. Third, you can recall and dial the telephone numbers you have stored in Set-Up.

More information can be found in the VT240 Series Owner’s Manual.