General Instructions

Guidelines for the Use of Field 856 General Instructions Table of Contents | Index for this Section| Next page |

Guidelines for the Use of Field 856

General Instructions

Required subfields
Access methods
Use of Uniform Resource Locator
Library of Congress Practice

No single subfield is required in all cases. Which ones are used largely depends on the access method indicated in the first indicator or in $2 (if first indicator=7).

In several of the situations below for which specific subfields are given, subfield $u (Uniform Resource Locator) may be used instead of a group of specific subfields.

If 1st indicator = 0 (email), the following subfields are used:

$a Host name
$f Electronic name

May also use: $b, $h, $i, $m, $n, $s, $x, $z
Unlikely to use: $c, $d, $k, $l, $o, $p, $t, $2

Those not listed can theoretically be used but no examples have been identified.

This is equivalent to URL mailto: scheme.

If 1st indicator = 1 (ftp), the following subfields are used:

$a Host name (or can use unique elements in $d and/or $f below and omit $a)
$d Path
$f Electronic name

May also use: $b, $c, $g, $i, $k, $l, $m, $n, $o, $p, $q, $s, $x, $3
Unlikely to use: $h, $t, $2

Those not listed can theoretically be used but no examples have been identified.

This is equivalent to URL ftp: scheme.

If 1st indicator = 2 (Remote login), the following subfield is used:

$a Host name

May also use: $b, $k, $l, $m, $n, $o, $p, $t, $x, $z, $3
Unlikely to use: $c, $d, $f, $g, $q, $s, $2

Those not listed can theoretically be used but no examples have been identified.

This is equivalent to URL telnet: scheme.

$2 Access Methods

If 1st indicator = 7 (Method specified in subfield $2):

$u Uniform Resource Locator
$2 Access method

Any subfields may be used depending on the access method. This approach may be used for a variety of circumstances. The following access methods that do not have a specific indicator value may be indicated in subfield $2:

http: Hypertext Transfer Protocol
gopher: Gopher protocol
news: USENET news
nntp: USENET news using NNTP access
wais: Wide Area Information Servers
file: Host-specific file names
prospero: Prospero Directory Service

For those access methods that do have an indicator value (ftp, telnet, electronic mail), the URL can still be recorded in $u with the correct indicator value recorded.

Use of Uniform Resource Locator

For any of the above, a Uniform Resource Locator (URL) can be used in subfield $u instead of parsing the data into separate subfields. A URL may also be used in addition to the separate subfields, if it is desirable to display data in a particular way; it is unlikely that LC will do this. If a URL is used instead of separate subfields, it is unlikely that other subfields will be used except in some circumstances $n (Name of location of host) and/or $3 (Materials specified; indicates a subset of the bibliographic item that is available electronically).

Library of Congress Practice

At LC, all subfields defined as of February 1994 have been validated across formats. Field 856 has been used at LC as follows:

World Wide Web linkage: Bibliographic records are being linked to electronic files accessible through LC's WWW server. Some of these are items that have a table of contents outside of the bibliographic record available electronically. Others may be computer file records for items available electronically (through WWW). It is expected that this use will be extended to other electronic resources that need to be linked to MARC records. These typically include the following subfields:

$u, $n, $3

Prints and Photographs Division/American Memory records: Records for items that have been digitized (or otherwise made available electronically) as part of American Memory projects may contain field 856 (data previously used in local field 938). First indicator has been set to 7 with subfield $2 "file" as access method. These typically include the following subfields:

$d, $f, $3; sometimes $g, $n

Subfield $a (Host name) is not used, because the system uses the unique information in $d and $f to provide access through a locator table on a remote host.

The following changes were approved by the USMARC Advisory Group at its American Library Association meetings in February 1995 and June 1994. They will be incorporated into Update No. 1 to the USMARC Format for Bibliographic Data in the near future.

1st indicator value 3 Dial-up
$j Bits per second (BPS)
$r Settings
$v Hours access method is available
$w Record control number

Attachment A is an updated version of field 856 including June 1994 and February 1995 changes.

Attachment B shows LC examples.

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Rev. 12/13/95 dih