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Quick Guide to Understanding the Documentation
For the GPO Photocomposition Coding Scheme
Of the U.S. Code
The GPO photocomposition code scheme was originally (in the mid-1970s) designed to
work on a GOP-modified version of the ATEX text editing system from Digital
Equipment Corp. The software to handle typesetting was the MTP (“Multi-Typography
Program”) developed in-house by GPO. In 1996, the ATEX system in the Office of the
Law Revision Counsel was replaced with XYWrite (a PC-based clone of ATEX). At
roughly the same time, the MTP software was replaced by MicroComp (also developed
in-house by GPO).
Photocomposition coded U.S. Code data consists of a stream of data with typesetting
instructions contained in character strings that follow one of several special characters.
The most widely used command character is the bell (HEX 07).
Bell codes
A bell (HEX 07) signals that a command is to be given. The character that immediately
follows a bell indicates the type of command. Some of these commands have arguments
– these arguments come immediately after the character following the bell. For instance,
Bell-I80
is a bell-I with an argument of 80. Note that the bell commands are case sensitive.
A brief description of each type of bell-code is contained on the attached copy of page 4
of GPO Coding for Selected Publications: Standardized locator lists and marked up
samples showing how to key selected publications, U.S. Government Printing Office,
February 1988:
Formats and Locators (Bell-F, Bell-S, and Bell-I)
Formats are designated by a four- or five-digit number that follows a bell-F or bell-S.
Each format is associated with a set of definitions for 99 bell-I codes (bell-I01 to bellI99). The bell-I codes (often referred to as “locator codes”) retain their definitions as
long as the format number does not change. When the format number changes, the
definitions for each of the locators codes change (e.g., the meaning of a locator-10 that
occurs while the format is 5800 has a different meaning from a locator-10 that occurs
while the format is 5804).
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The following tables define the 99 locator codes associated with each U.S. Code format.
The headings of the table have the following meanings:
LOC
PTSZ
LDG
LGH
INDENT PRI
INDENT SEC
GRID
TF
LNTP
FOTP
RULE
locator code
point size
leading (points from the baseline of one character to the
baseline of the character above it)
line length in points
primary indent (the indent (in points) of the first line of a
paragraph)
secondary indent (the indent (in points) of all lines in a
paragraph after the first line)
grid call – see “Grids and Typefaces,” below
typeface call – see “Grids and Typefaces,” below
line type (C = center, J = justify, L = flush left, and R =
flush right)
format type (used to format rudimentary tabular data, e.g.,
tables of contents) – if the previous locator code had a
numeric FOTP value and the current locator code has a
numeric FOTP value that is greater than the FOTP value of
the previous locator code, then do not start a new line.
if the RULE value is “R”, then generate a horizontal rule.
(Additional definitions may be found in Publishing From a Full Text Data Base,
Government Printing Office, Graphic Systems Development Division, GPO Publication
200.4 (2nd edition), February 1983).
There are no separate tables for formats 5801, 5802, and 5803, because the locator code
definitions within those three formats are the same as the definitions for format 5800.1
For the most part, formats 5801 to 5803 are only used in U.S. Code appendices (e.g., the
appendix to title 5).
Additional documentation is available for format 5800
and for format 5804
1
The only exceptions to this are (1) the number of lines within the running heads and (2) whether or not the
first page must start on an odd page number.
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With the format 5800 documentation, you should add the following:
 Locator-86 includes Presidential Proclamations, but does not include Reorganization
Plans
 Locator-87 includes Definition notes
Grids and Typefaces – bell-G, bell-g, bell-K, and bell-T
The typeface and type style (bold, italic, etc.) are specified by a combination of a grid call
and a typeface call. Each locator code contains a default grid and typeface value. These
values can be overridden however. Bell-T followed by a one-digit argument will change
the typeface call to the value of the argument. Bell-G followed by a one-digit argument
(or bell-g followed by a three digit argument) will change the grid call to the value of the
argument. A bell-K will change the typeface and grid calls back to the defaults specified
by the last locator code.
When the current grid is the result of a bell-g with a three-digit argument, then the
typeface and type style of the text are as set out in pages i to xvii of MicroComp Grid
List, U.S. Government Printing Office, May 1996
Of the grids listed in MicroComp Grid List, the U.S. Code currently uses grids 007, 025,
077, 401, 710, 741, 742, and 940.
When the value of the grid call is 1 to 4 and the current grid is the result of either a bell-G
or the default value from a locator code, then use the table in the middle of page 4 of the
format 5800 documentation, above.
When the value of the current grid call is 5 to 8, use the following VideoComp table
Titles, Chapters, Parts, etc. (bell-R)
A bell-R followed by two digits, indicates the start of a new grouping above the section
level. The two-digit argument indicates where the grouping sits within the hierarchy.
The lower the bell-R argument, the higher in the hierarchy the grouping is. For example,
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a bell-R01 indicates the start of a new title – the highest hierarchical level within the U.S.
Code. By convention, bell-R05 is always used to indicate the start of a title appendix.
Tables (“subformat generation”) – bell-c
Complex tables start with a bell-c. The end of such a table is marked with a bell-e. In
between a bell-c and a bell-e most of the rules for how to process photocomposition
codes are replaced with the special rules set out in Subformat Generation: MicroComp,
U.S. Government Printing Office, February 1, 1997:
An addition to the 1997 documentation should be made on pages 2 and 5. A bell-I97 has
been added. The bell-I97 does the same function as the bell-I96, except that on a table
that is continued on the next page (or column of a page), a bell-I96 headnote will have
“—continued” automatically appended to the text of the headnote, whereas a bell-I97
headnote will not have “—continued” automatically appended.
Other Special Characters
In addition to the bell character, the following special characters are valid in Office of the
Law Revision Counsel publications:
Name
EOF
Sectwst
Crlf
Cents
Pgmark
Noprnst
Noprnend
Prime
Bldlbrak
Bldrbrak
Emspace
Enspace
Plusminus
Dscrhyph
Dagger
Xquotes (open)
Hex Value
00
06
0A
0B
0C
0E
0F
10
13
14
18
19
1B
1C
1E
27
Notes
End of file
§
Carriage return – line feed
¢
¶
No print – start
No print – end
'
Bold left bracket
Bold right bracket
M-space
N-space
±
Discretionary hyphen
†
“
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Name
Less than
Greater than
Footnote
Hex Value
3C
3E
5C
minus
Emdash
Xquotes (close)
Degreemk
Dbldagger
Muchless
Balbox
5E
5F
60
AB
BD
BE
BF
Notes
<
>
Convert numbers between
footnote characters
(backslashes) into
superscripts
–
”
º
‡

□
An escape character (Hex FF) followed by the following two (or three) characters
represents the following characters
Name
Thin space
N-dash
Multiplication
All Mark
Copyright
AC_BREVE
AC_ACUTE
AC_GRAVE
AC_CIRCUMFLEX
AC_DIERESIS
AC-CARON
AC_TILDE
AC_ANGSTROM
AC_MACRON
AC_CEDILLA
ESC sequence
ESC 1A
ESC 09
ESC 0A
ESC 08
ESC AF
ESC AE0
ESC AE1
ESC AE2
ESC AE3
ESC AE4
ESC AE5
ESC AE6
ESC AE7
ESC AE8
ESC AE9
Notes
Thin space
N-dash

O
©
˘
΄
`
^
¨
ˇ
~
˚
ˉ
¸
XHTML Conversion
All of the above documentation provides explanations for each of the photocomposition
codes used in the U.S. Code. Below is a proposed specification for converting U.S. Code
photocomposition codes into XHTML
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