Chapter 4
VT100 Options

The VT100 has available options which are designed to enhance the basic terminal and allow its use in a wide range of applications. The options currently available are:

In the future, additional options will be available which will further enhance the basic VT100. Contact the nearest DIGITAL Sales Office for further information and how to order the options.

Advanced Video Option – VT1XX-AB

The Advanced Video Option enhances the basic VT100 by adding the following features:

Advanced Video Option Installation

Use the following procedure to install the Advanced Video Option.

  1. Remove power from the terminal by disconnecting the ac plug.
  2. Unplug the keyboard (Figure 4-1).
  3. Unplug any connectors from the composite video input/output jacks.
  4. Disconnect the communications cable.
  5. With a blade-type screwdriver loosen the four captive screws holding the access cover.
  6. If the 20 mA Current Loop Option is installed, gently pull the access cover away from the terminal about 2 inches; then reach in and disconnect J5 from the terminal controller board.
  7. Remove the access cover.
  8. Remove any graphic or STP cables.
  9. Remove the terminal controller board by gently but firmly pulling the board straight out. The terminal controller board is located in the leftmost slot in the card cage (viewed from the rear).
  10. Place the terminal controller board on a flat surface with the component side up (Figure 4-2).
  11. Locate the four mounting holes drilled in the terminal controller board; mount a standoff in each.
  12. Grasp the advanced video board by the edges and carefully align the connector pins with the connector on the terminal controller board. Gently but firmly mount the advanced video board onto the terminal controller board.
  13. Reinstall the terminal controller board. The terminal controller board must be inserted into the leftmost slot in the card cage.
  14. Reinstall all cables removed.
  15. Reinstall the access cover.

Advanced Video Option Checkout

Use the following procedure to check out the operation of the Advanced Video Option.

  1. Turn the terminal power on and verify that no error was detected during the power up self-test.
  2. Press the SET-UP key. The words "SET-UP A" should blink in boldface, the words "TO EXIT PRESS SET-UP" should be underlined, and the ruler should contain alternating normal and reverse video fields.
  3. Place the terminal in the 132-column mode and then in the LOCAL mode.
  4. Exit SET-UP and type the following sequence:

    ESC < ESC # 8

    The screen should now display 24 lines × 132 columns.

20 mA Current Loop Option – VT1XX-AA

The 20 mA Current Loop Option allows the VT100 to connect directly to the host computer over a short distance without using a modem. The specifications for the 20 mA Current Loop Option are located in Chapter 2 of this manual under interface information.

20 mA Current Loop Option Installation

Use the following procedure to install the 20 mA Current Loop Option:

  1. Remove power from the terminal by disconnecting the ac plug.
  2. Unplug the keyboard.
  3. Unplug any connectors from the composite video input/output jacks.
  4. Disconnect the communications cable.
  5. With a blade-type screwdriver loosen the four captive screws holding the access cover; then remove the cover.
  6. Set the TRANS switch to the NORMAL position (Figure 4-3). (If the terminal must provide current on the receive line, set the switch to the ACT position).
  7. Set the REC switch to the NORMAL position (Figure 4-3). (If the terminal must provide current on the receive line set the switch to the ACT position).
  8. Connect P5 to J5 on the terminal controller board (Figure 4-4).
  9. Perform the 20 mA Current Loop Option Checkout.

20 mA Current Loop Option Checkout

The VT100 contains an internal test called the data loopback test. In the data loopback test the VT100 transmit and receive lines are connected to each other via a special external connector. A predefined set of characters are then transmitted. The terminal receives the characters and compares them to the characters transmitted. If the characters do not match an error is then flagged.

Use the following procedure to check out the operation of the 20 mA Current Loop Option.

  1. Disconnect the terminal from the communications line.
  2. Remove the terminal access cover containing the 20 mA current loop board; place both of the switches in the NORMAL position. Reinstall the access cover.
  3. Connect the 20 mA loopback connector (PN 70-15503-00) to the Mate-N-Lok connector mounted to the bottom of the access cover.
  4. Place the terminal in ANSI-compatible mode (in SET-UP B group 2 switch 3 equals a 1).
  5. Type the following sequence to perform the data loopback test.

    ESC [ 2 ; 2 y

    When the test is performed, the screen clears and the message "WAIT" is displayed in the upper left corner of the screen. The entire test takes approximately six seconds to run.

    NOTE: The data loopback test can be repeated indefinitely by typing ESC [ 2; 10 y. This test ends only when an error is detected or the terminal power is turned off.

  6. A loopback error is shown by "8" being displayed in the upper left corner of the screen. If an error is detected, check the 20 mA board connectors and switch settings and then repeat Step 5. If the error persists, contact your service organization.
  7. Once the test is complete return the 20 mA current loop board switches to the original positions, remove the loopback connector, replace the access cover, and reconnect the terminal to communications line.

Communications Cables

The communications cables available for use with the VT100 are listed in Chapter 5.