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INTECOLOR-VHR19 [28-Apr-84]; [16-May-84]

 The Intecolor VHR19 terminal was introduced on the market in September,
 1983, but I was able to obtain one  for test only at the end of  April,
 1984.  It was announced at an introductory price of $3995, the same  as
 the Tektronix 4105 and the  Chromatics 4200.  Comparisons will be  made
 with these terminals, and  a separate section in  this document on  the
 comparison of the Tektronix and  Chromatics should be read for  further
 details.

 The test model  I received had  version 1.00 firmware,  and during  the
 test, we received version 1.10 which corrected some problems we had  in
 alphanumeric mode.   The manual  is marked  "***** Preliminary  Version
 *****", so I expect that  Intecolor has plans for additional  features.
 It is reasonably well written,  particularly in the section about  ANSI
 terminal commands, and has a comprehensive index.

 The VHR19 features a 19-inch 60Hz color monitor and a separate box  for
 frame buffer and power  supply which connects to  the monitor via  four
 coaxial cables (red, green, blue, and  sync); the frame buffer box  can
 sit beside or under the monitor.  In addition to a host RS-232C  serial
 port on the box, there is a DMA input/output (parallel and serial) port
 for a video camera or printer, and an auxiliary RS-232C serial port for
 a trackball or digitizing  tablet.  Serial baud  rates up to  19.2Kbaud
 are supported.  The terminal supports pan and zoom (in steps of 1 to 8)
 selectable both locally and by the host.

 The frame buffer  contains three 1024  x 1024 memory  planes (giving  8
 colors), each with its own  NEC Graphics Display Controller chip.   The
 terminal itself  uses  a  4MHz  Z80A  microprocessor  for  alphanumeric
 control, and displays 32  lines of 80  very readable large  characters.
 In text mode, the foreground and background color of every character on
 the screen can be selected independently.

 The keyboard is  attached with  a flexible  coiled cable  to the  frame
 buffer box and has a DEC VT100 layout with 23 function keys in two rows
 above the upper  row of digit  keys.  The function  keys can be  loaded
 with separate  sequences of  up to  40 characters  each for  unshifted,
 shifted, and control states, giving 69  function keys in all.  If  they
 are not user defined, they send default three-character escape sequence
 "<ESC>Ox".  Unfortunately,  the  function  keys  can  only  be  locally
 defined, not downloaded from the host.

 The  VHR19  emulates  the   Tektronix  4010/4014  monochrome   graphics
 displays, the Intecolor graphics mode, as well as ANSI (VT100) and VT52
 alphanumeric terminal  modes.   These four  can  be host  selected  via
 escape sequences, or  selected locally  (without loss  of screen  data)
 from a menu.  All terminal  settings are selectable from a  color-coded
 menu.  The input buffer size is 4K, which is large enough that I  never
 observed any data loss at 9600 baud during the test.

 The graphics speed of the terminal is quite good.  A test at 9600  baud
 drawing vectors from the upper left screen corner to every point on the
 right and bottom edges and then back again with color black showed that
 the line drawing algorithm is  symmetric (a good point).  In  Intecolor
 mode with verbose  commands, this  test took 66  seconds; in  Tektronix
 mode with compact vectors, it took  21 seconds.  With the display  size
 of 1024 x 768, an average vector  in this test is at least 1086  pixels
 long, so the total number  of pixels set was about  2 * (1024 + 768)  *
 1086 =  3.89M,  giving  a  drawing rate  of  185K  pixels/sec  (or  5.4
 microsec/pixel)  in  Tektronix  mode   and  59K  pixels/sec  (or   16.9
 microsec/pixel) in Intecolor mode.

 Rectangle fills of the 1024 x 768  screen area take about 4 sec  (about
 196K pixels/sec, or  5.1 microsec/pixel),  and  fills  of  screen-sized
 circles take about 13 sec.

 For comparison, it should be noted  that with a microprocessor such  as
 the Intel 8088  used in  the IBM  Personal Computer,  even with  highly
 optimized assembly  code,  it is  not  possible to  generate  arbitrary
 vectors faster than about 30 microsec/pixel.

 I was not able  to get the  VHR19 to use  color in Tektronix  4010/4014
 mode, but the  factory claims  that this is  provided for  but not  yet
 documented.

 In Intecolor graphics mode, commands take the form

 <letter>,<digitstring>,<digitstring>,<digitstring>,...

 Functions available include:

 Pan                            Rectangle
 Zoom                           Circle
 Point                          Arc
 Relative Point                 Polyline
 Vector                         B-spline Curve
 Relative Vector                Filled Polygon
 Concatenated Vector            Filled Relative Polygon
 Read Position                  Filled Pie Slice
 Read                           Super Pixel
 Select Color                   Display Super Pixel
 Initialize to Default Color    Super Pixel Bar
 Change Color                   Set Fill Pattern
 4027 Color Definition          Set Line Style
 Fill Screen                    Clear Screen
 Select Display Planes          Write
 DMA Read/Write

 The read  and  write  commands  allow  selection  of  a  pixel  in  any
 combination of the three memory planes.  The area fill patterns include
 a user-definable 8 x 8 bit  pattern, 16 built-in patterns, and  pattern
 numbers outside  the range  0  ..  16  select unusual  but  predictable
 patterns (presumably  related  to their  binary  representation).   The
 colors may be  selected from  a default set  of 8  (black, red,  green,
 yellow, blue,  magenta,  cyan, and  white)  corresponding to  the  CORE
 system  basic  set,  or  they  may  be  individually  defined  in   the
 red-green-blue model  or  the Tektronix  4027  hue-lightness-saturation
 model.  Super  pixels  are  4 x  4  blocks  with colors  based  on  the
 hue-lightness-intensity model; so much data is required to define  them
 that except  for  filled  bars,  they  are  of  little  use.   The  DMA
 Read/Write may be  a way of  supporting display of  raster images,  but
 insufficient detail is given to make it usable.  The factory assures me
 that a  manual describing  the  hardware ports  is in  preparation  and
 should soon be available.

 Tests of rectangle  and concave  polygon fill  were made  on the  VHR19
 similar to  the  ones  performed  earlier on  the  Tektronix  4105  and
 Chromatics 4200.  None is  noticeably slower than  the others when  the
 different screen resolutions are taken into account.  Concave  polygons
 (five-pointed stars) were correctly filled.

 Each of these three  terminals has  desirable features,  so that it  is
 difficult to make a choice between them.  The Tektronix 4105 has raster
 image display capability and a color lookup table which can be adjusted
 locally from a superb menu setup, but it has low resolution and neither
 zoom nor pan.  The  Chromatics 4200 is  more powerful graphically  than
 the other two, with 16 colors, zoom and pan, polygon flood fill,  thick
 vectors, and  by  now  should  have color  lookup  table  support  (our
 December  1983  demonstrator  did  not).   Its  alphanumeric   terminal
 emulation is  only an  ADM3A, which  lacks partial  erase  capabilities
 forcing excessive blank padding (and thus slow redisplay) by a  display
 editor, and the  model we had  lost characters badly  above 2400  baud.
 The Intecolor VHR19  has double  the resolution,  zoom and  pan, and  a
 large screen, and  an adequate  supply of  vector graphics  primitives,
 though I  would very  much  like to  have  these available  in  compact
 Tektronix vector format  to triple the  already acceptable speed.   The
 factory claims  that  a  compact  vector  format  (different  than  the
 Tektronix one) will be supported in the near future.

 Note added 16-May-84: I liked this terminal well enough of the three in
 its  league  to  buy  one,  though  if  Chromatics  had  resolved   the
 alphanumeric problem,  I might  have chosen  the 4200  instead.  A  big
 point for me is the resolution of the VHR19.