COMMENT ⊗   VALID 00004 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	.device xgp
C00003 00003	.next page select 2 center
C00005 00004	.next page select 2 once center
C00006 ENDMK
C⊗;
.device xgp
.PAGE FRAME 80 WIDE 53 HIGH;
.AREA TEXT LINE 4 TO 51;
.font 1 "bdr40"; font 2 "bdr66"; turn on "≡" for "%";
.font 3 "fix40";
.center; select 2;
.place text
foo
.next page
Document Representation in
Computer Communication Systems
.nofill

Where we are going.
.select 1
    Computer mail, news, publications, ...


.select 2;
Where we are.
.select 1
    Prototype networks, irregular character sets, no graphics.


.select 2;
What do we need?
.select 1
    a.  A universal symbol set,

    b.  A graphical communication language.

    c.  Graphical compilers (medium specific)

.next page; select 2; center
A 16 bit Standard Code


.nofill; select 3;
Code: '0                 IG         LG     
     International standard  ad hoc   Local
        graphics symbols      grfx    grfx



 |       LC         IC      '177777
 | Local    ad hoc     International
 | control  control      control

. next page; select 2; center
Communication Protocol


.nofill
Header:

.select 3;

# of bits:      16             16           16
Field:     message type   # of symbols   byte size


.select 2;
Code pairs:

.select 3;
# of bits:       16         (specified in header)
Field:      standard code    transmission code

.next page; select 2; once center
PUB FEATURES


.SELECT 1
ALGOL-like syntax

Multiple device output

Format control (headings, footnotes, columns, justification)

Font selection

Macros

Counters

Symbolic cross-references

Automatic table of contents, sorted index

Interactive debugging

(Extension) line drawings