Installing and Using the VT420 Video Terminal


This appendix lists the specifications for the worldwide version of the VT420 video terminal.

Site Planning

VT420 Terminal (Approximate Size)
Height 282 mm (11.1 in)
Width 320 mm (12.6 in)
Depth 331 mm (13.1 in)
Weight 8 kg (17.5 lb)
Tilt-swivel 60 degrees
Adjustable tilt +5 to -20 degrees
LK401 Keyboard (Approximate Size)
Height 45 mm (1.75 in)
Width 478 mm (18.8 in)
Depth 191 mm (7.5 in)
Weight 1.4 kg (3.1 lb)

Operating Environment

Temperature 10° to 40° C (50° to 104° F)
Relative humidity 10% to 90% relative humidity wih a maximum wet bulb of 280° C and a minimum dew point of 2° C
Altitude 2400 m (8000 ft) maximum


AC input No selection required. 100 to 240 V nominal, single-phase, 2-wire plus safety earth ground, 88 to 264 Vrms preset voltage
Line frequency 50 to 60 Hz nominal
Input power 67 watts
Power cord North American: Rated 125 V, listed, type SJT/SVT, 18 AWG-3 wire
All others: Rated 250 V, "HAR" cordage, 0.75 mm²


Active video area (approximate size)
   Horizontal 232 mm (9.04 in)
   Vertical 168 mm (6.55 in)
Format 24, 36, or 48 lines of 80 or 132 characters
Built-in character sets DEC Multinational character set
DEC Supplemental
ISO Latin Alphabet No. 1
ISO Latin-1 Supplemental
DEC Special Graphics
DEC Technical
11 National replacement character sets
Video attributes Normal, bold, underline, blinking, and negative image (reverse video) -- selected individually or in combination
Text cursor Blinking or steady block or underline
Frame rate 70 Hz (60 Hz optimal)
Antiglare Integral with CRT

LK401 Keyboard


108 sculptured keys with matte finish

Available in 16 language dialects and 15 word processing versions, including English. Three French language keyboards.

Cord 1.8 (6 ft) coiled cord with a 4-pin telephone-type modular connector
Indicator lights

2 keyboard indicators:

Keys (Approximate Size)
Home row 30 mm (1.18 in) above desktop
Key size 13 mm (0.50 in) square
Key spacing 19 mm (0.75 in) center to center (for single-width keys)
Numeric keypad 18 keys
Function keys 5 predefined keys, 15 user-definable keys
Audible Indicators
Keyclick Sounds after each keystroke.
Margin bell Rings once when cursor approaches right margin.
Warning bell Rings once for compose errors.
Rings twice for errors in set-up.
Rings once upon receipt of Ctrl G.