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VT320

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VT320
A VT320 with an LK201 keyboard (Adamantios, CC BY-SA 3.0)
Manufacturer Digital Equipment Corporation
Type Video terminal
Release date 1987[1]
Interface 6-pin DEC-423 host and printer ports; 25-pin RS-232 host port (international model)[2]
Dimensions 25.27 × 31.36 × 31.49 cm (H × W × D)[3]
Weight 6.6 kg (terminal), 2 kg (keyboard)[3]
Predecessor VT220
Successor VT420
Model VT320-A2, -B2, -C2 (North American); VT320-A3, -B3, -C3, -G2, -H2, -J2 (international)[4]
Power 50 W maximum; 100–120 V or 220–240 V nominal[3]

The VT320 is a monochrome text terminal made by Digital Equipment Corporation and introduced in 1987 as the text-only model of the VT300 series.[1] It is compatible with the VT220, has a 14-inch flat screen showing 24 lines of 80 or 132 characters plus a status line, and uses the LK201 keyboard.[2][4]

Inside are a separate power supply assembly and a single board that carries both the terminal logic and the monitor circuits. Read CRT Discharge Procedure before working inside; DEC's service guide warns that removing the CRT exposes the anode and its stored charge.[5]

History

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The VT300 series replaced the VT200 series as a cheaper range able to compete with VT220-compatible terminals from other makers; the VT330 and VT340 added graphics. The VT320 added ISO Latin-1 to the VT220's multinational character set.[1][6] It was replaced by the VT420 in 1990.[1] Sources differ on the launch price: Wikipedia's VT320 article gives US$495, while its VT220 article gives US$545 for the VT300 series.[1][7]

Specifications

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VT320 specifications (DEC, EK-VT320-UU-001, Appendix A)
Item Specification
CRT 35.6 cm (14 in) monochrome, flat antiglare screen
Format 24 lines of 80 or 132 characters, plus a status line
Line voltage 100–120 V or 220–240 V nominal; 50–60 Hz
Input power 50 W maximum
Terminal 25.27 cm high, 31.36 cm wide, 31.49 cm deep; 6.6 kg
Keyboard 5.1 × 53.3 × 17.1 cm; 2 kg

[3][2]

Hardware

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Models

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DEC made two basic models. The North American model has a single 6-pin DEC-423 communication port and an attached power cord, and does not support the national replacement character sets. The international model adds a 25-pin RS-232 port, supports the NRC sets and has a detachable cord; its power supply has a voltage jumper. Each was sold with a white, green or amber screen.[2][8][4]

VT320 field-replaceable units (DEC recommended spares)
Unit Part number
Monitor and logic with arc protection, North American 70-24577-01
Monitor and logic with arc protection, international 70-24577-02
Power supply, North American 70-24244-01
Power supply, international 70-24244-02
CRT/bezel/yoke, paper white / green / amber 70-24240-01 / -02 / -03
Access cover; bottom assembly 70-24242-01; 70-24245-01
Loopback connectors, DEC-423 and RS-232 12-25083-01; 12-15336-00

[9]

The power supply carries a green DC OK LED, visible through the ventilation slots on top of the terminal.[10] The power supply module drawn as 5417191 in DEC's print set has a 3 A 250 V fuse, F501, on its board; the print set also contains a second supply design, 5417279.[11] The monitor and logic board takes CRTs from two makers, Philips and Clinton, and a jumper (J7 for Philips, J8 for Clinton) must match the maker named on the label on top of the CRT.[12] A small arc protection board fits on the CRT neck.[13]

Paul Williams lists the main chips on the board of a 1988 VT320-C3: a Siemens SAB8031A (ROMless 8051), a Motorola MC2681 DUART, a Toshiba TC53512 64 KB ROM, two TC5565 8 KB static RAMs, an ST TDA1170N vertical deflection IC, and a Microchip ER5911 serial EEPROM of 128 bytes.[14]

Keyboard

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The VT320 uses the LK201, connected by a coiled cable (BCC01) to a socket on the right side of the terminal. Pin 3 of the keyboard connector carries +12 V.[12][15] DEC's VT320 spares list gives an LK201 variant for each language, with different suffixes from the VT220 list.[9]

Known faults

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DEC's troubleshooting table puts almost every fault that is not a set-up error on the monitor and logic with arc protection assembly; a blank screen is narrowed down with the DC OK LED (see VT320 Troubleshooting Guide).[16] Error codes:

  • "VT320 NVR Error - 1": DEC's fix is to select Default and Save in set-up and power-cycle, and only then replace the monitor and logic assembly.[17]
  • "VT320 Keyboard Error - 4": check the keyboard is plugged in, then replace the keyboard.[17]

See also VT320 General Maintenance and VT320 CRT Service Guide.

Documentation

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Details are on VT320 Documentation.

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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 "VT320", Wikipedia, en.wikipedia.org/wiki/VT320. Introduction in 1987, VT330 and VT340, competition, price, replacement by the VT420 in 1990.
  2. ↑ 2.0 2.1 2.2 2.3 DEC, EK-VT320-PS-001, pp. v to vi, "The VT320 Video Terminal". Screen, format, models and ports.
  3. ↑ 3.0 3.1 3.2 3.3 Digital Equipment Corporation, Installing and Using the VT320 Video Terminal, EK-VT320-UU-001, June 1987, p. 60, Appendix A (File:Installing and Using the VT320 Video Terminal (EK-VT320-UU-001).pdf).
  4. ↑ 4.0 4.1 4.2 DEC, EK-VT320-PS-001, p. 47, Appendix B, "VT320 Models".
  5. ↑ DEC, EK-VT320-PS-001, p. 25, section 2.4. Anode discharge warning.
  6. ↑ Paul Flo Williams, "25 Years of DEC Video Terminals", VT100.net, vt100.net/dec/vt_history. VT320 and ISO Latin-1.
  7. ↑ "VT220", Wikipedia, en.wikipedia.org/wiki/VT220. VT300 series price.
  8. ↑ DEC, EK-VT320-PS-001, p. 24, section 2.3. Voltage jumper on the international power supply.
  9. ↑ 9.0 9.1 DEC, EK-VT320-PS-001, p. 48, "VT320 Recommended Spares List".
  10. ↑ Digital Equipment Corporation, VT320 Pocket Service Guide, EK-VT320-PS-001, first edition, July 1987, pp. 1 to 2, section 1.2 and Figure 1-1 (File:VT320 Pocket Service Guide (EK-VT320-PS-001).pdf). DC OK indicator.
  11. ↑ Digital Equipment Corporation, VT320 Field Maintenance Print Set, MP02509-01 revision E, July 1987, power supply module 5417191 parts list, sheet A2 (PDF p. 26) (File:VT320 Field Maintenance Print Set (MP02509-01 rev E).pdf). Fuse F501.
  12. ↑ 12.0 12.1 DEC, EK-VT320-PS-001, p. 33, sections 2.5 and 2.6. CRT maker jumpers; keyboard connector.
  13. ↑ DEC, EK-VT320-PS-001, p. 27, section 2.4. Arc protection board on the CRT neck.
  14. ↑ Paul Flo Williams, "Digital VT320 Component List", VT100.net, 1998, vt100.net/dec/vt320/components. Chips on the board of one VT320-C3 made in Hong Kong in 1988.
  15. ↑ DEC, EK-VT320-PS-001, pp. 46 and 49, Appendix A keyboard cable and Appendix C connector pinout.
  16. ↑ DEC, EK-VT320-PS-001, pp. 3 to 6, Figure 1-2 and Table 1-1.
  17. ↑ 17.0 17.1 DEC, EK-VT320-PS-001, p. 18, Table 1-3, "VT320 Display Error Codes".
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