Library of Congress >> MARC >> Holdings >> 852 & 856 >> 856

856 - Electronic Location and Access (R)

MARC 21 Holdings - Full
October 2003

First Indicator
Access method
# - No information provided
0 - Email
1 - FTP
2 - Remote login (Telnet)
3 - Dial-up
4 - HTTP
7 - Method specified in subfield $2

Second Indicator
# - No information provided
0 - Resource
1 - Version of resource
2 - Related resource
8 - No display constant generated

Subfield Codes
$a - Host name (R)
$b - Access number (R)
$c - Compression information (R)
$d - Path (R)
$f - Electronic name (R)
$h - Processor of request (NR)
$i - Instruction (R)
$j - Bits per second (NR)
$k - Password (NR)
$l - Logon (NR)
$m - Contact for access assistance (R)
$n - Name of location of host (NR)
$o - Operating system (NR)
$p - Port (NR)
$q - Electronic format type (NR)
$r - Settings (NR)
$s - File size (R)
$t - Terminal emulation (R)
$u - Uniform Resource Identifier (R)
$v - Hours access method available (R)
$w - Record control number (R)
$x - Nonpublic note (R)
$y - Link text (R)
$z - Public note (R)
$2 - Access method (NR)
$3 - Materials specified (NR)
$6 - Linkage (NR)
$8 - Field link and sequence number (R)


Information required to locate an electronic resource. The information identifies the electronic location containing the resource or from which it is available. It also contains information needed to retrieve the resource by the access method identified in the first indicator position. The relationship of the electronic location and access information in field 856 to the resource identified by the record as a whole is identified by the second indicator. The information contained in this field is sufficient to allow for the electronic transfer of a file, subscription to an electronic journal, or logon to an electronic resource. In some cases, only unique data elements are recorded which allow the user to access a locator table on a remote host containing the remaining information needed to access the resource.

Field 856 is repeated when the location data elements vary (the URL in subfield $u or subfields $a, $b, $d, when used). It is also repeated when more than one access method is used, different portions of the item are available electronically, mirror sites are recorded, different formats/resolutions with different URLs are indicated, and related items are recorded.

See the Guidelines for the Use of Field 856 for a more thorough discussion on the use of field 856.

This field is identical to field 856 (Electronic Location and Access) defined in the MARC 21 Format for Bibliographic Data.



First Indicator - Access method
If the resource is available by more than one access method, the field is repeated with data appropriate to each method. When recording a URL in subfield $u, the value corresponds to the access method (URL scheme), which is also the first element in the string.
The methods defined are the main TCP/IP (Transmission Control Protocol/Internet Protocol) protocols.
# - No information provided
Used when subfield $u contains a URN and there is no URL recorded. When subfield $u contains a URL and the subfield is repeated with a URN, the indicator value for the appropriate access method of the URL is given.
856 ##$uurn:doi:10.1000/100
0 - Email
Access to the electronic resource is through electronic mail (email). Includes subscribing to an electronic journal or electronic forum through software intended to be used by an email system.
856 0#$$iejap subscription
1 - FTP
Access is through the File Transfer Protocol (FTP).
856 1#$u
2 - Remote login (Telnet)
3 - Dial-up
Access is through a conventional telephone line (dial-up).Additional information in subfields of the record may enable the user to connect to the resource.
856 3#$$b140.147.254.3$$t3270$tline mode (e.g., vt100)$vM-F 6:00 a.m.-21:30 p.m. USA EST, Sat. 8:30-17:00 USA EST, Sun. 13:00-17:00 USA EST
4 - HTTP
Access is through the Hypertext Transfer Protocol (HTTP).
856 40$u
856 4#$u$uurn:hdl.loc.test/gotthome
7 - Method specified in subfield $2
Access is through a method other than the defined values and for which an identifying code is given in subfield $2 (Source of access).
856 7#$3b&w film copy neg.$ddag$f3d01926$2file
Second Indicator - Relationship
Relationship between the electronic resource at the location specified in field 856 and the item described in the record as a whole.
Used to provide further information about the relationship if it is not a one-to-one relationship.
# - No information provided
0 - Resource
Electronic location in field 856 is for the same resource described by the record as a whole. In this case, the item represented by the bibliographic record is an electronic resource. If the data in field 856 relates to a constituent unit of the resource represented by the record, subfield $3 is used to specify the portion(s) to which the field applies. The display constant Electronic resource: may be generated.
856 40$u
1 - Version of resource
Location in field 856 is for the same resource described by the record as a whole. In this case, the item represented by the bibliographic record is not electronic but an electronic version is available. If the data in field 856 relates to a constituent unit of the resource represented by the record, subfield $3 is used to specify the portion(s) to which the field applies. The display constant Electronic version: may be generated.
856 41$u
856 41$3Table of contents$u
2 - Related resource
Location in field 856 is for an electronic resource that is related to the bibliographic item described by the record. In this case, the item represented by the bibliographic record is not the electronic resource itself. Subfield $3 can be used to further characterize the relationship between the electronic item identified in field 856 and the item represented by the bibliographic record as a whole. The display constant Related electronic esource: may be generated.
856 42$3Finding aid$u
8 - No display constant generated


$a - Host name
Fully qualified domain (host name) of the electronic location. It contains a network address which is repeated if there is more than one address for the same host.
$b - Access number
Access number associated with a host. It can contain the Internet Protocol (IP) numeric address if the item is an Internet resource, or a telephone number if dial-up access is provided through a telephone line. This data changes frequently and may be generated by the system, rather than statically stored.
May be repeated if all the other information in the field applies.
$c - Compression information
In particular, whether a specific program is required to decompress the file.
May be repeated if two compression programs are used, noting the latest compression first.
$d - Path
Path, the series of logical directory and subdirectory names that indicate where a file is stored. The filename itself is recorded in subfield $f. This may be a surrogate path leading the user to the host where complete and current access information is stored in a locator table.
$f - Electronic name
Electronic name of a file as it exists in the directory/subdirectory indicated in subfield $d on the host identified in subfield $a. May be repeated if a single logical file has been divided into parts and stored under different names. In this case, the separate parts should constitute a single bibliographic item. In all other cases, a file that may be retrieved under different filenames contains multiple occurrences of field 856, each with its corresponding electronic name in subfield $f. A filename may include wildcard characters (e.g., * or ?) if applicable. Use subfield $z to explain how files are named, if needed.
$h - Processor of request
Username, or processor of the request; generally the data which precedes the at sign (@) in the host address.
$i - Instruction
Instruction or command needed for the remote host to process a request.
$j - Bits per second
Lowest and highest number of bits (binary units) of data that can be transmitted per second when connected to a host. The syntax for recording the number of bits per second (BPS) should be: <Lowest BPS>-<Highest BPS>. If only lowest given: <Lowest BPS>- ; If only highest given: -<Highest BPS>.
$k - Password
Password required to access the electronic resource. An FTP site may require the user to enter an Internet Protocol address or may require a specific password. Electronically accessed catalogs may also require a password. If a system that requires a password will accept anything entered as valid, this subfield can be omitted from field 856. This subfield is used to record general-use passwords, and should not contain passwords requiring security. Textual instructions about passwords are contained in subfield $z (Public note).
$l - Logon
Characters needed to connect (i.e., logon, login, etc.) to an electronic resource or FTP site. Used to record general-use logon strings which do not require special security.
$m - Contact for access assistance
Name of a contact for assistance in accessing a resource at the host specified in subfield $a. For addresses relating to the content of the resource itself (i.e. the item represented by the title recorded in field 245) rather than access assistance, field 270 is used. If the address data is the same, use field 270.
$n - Name of location of host
Conventional name of the location of the host in subfield $a, including its physical (geographic) location.
$o - Operating system
For informational purposes, the operating system used by the host specified in subfield $a may be indicated here. Conventions for the path and filenames may be dependent on the operating system of the host. For the operating system of the resource itself (i.e., the item represented by the title recorded in field 245), rather than the operating system of the host making it available, field 753 (Technical Details Access to Computer Files), subfield $c (Operating system) is used.
$p - Port
Portion of the address that identifies a process or service in the host.
$q - Electronic format type
Identification of the electronic format type, which is the data representation of the resource, such as text/html, ASCII, Postscript file, executable application, or JPEG image. Electronic format type may be taken from enumerated lists such as registered Internet Media Types (MIME types).
The intent of specifying this element is to provide information necessary to allow people or machines to make decisions about the usability of the encoded data (what hardware and software might be required to display or execute it, for example). The electronic format type also determines the file transfer mode, or how data are transferred through a network. (Usually, a text file can be transferred as character data which generally restricts the text to characters in the ASCII (American National Standard Code for Information Interchange (ANSI X3.4)) character set (i.e., the basic Latin alphabet, digits 0-9, a few special characters, and most punctuation marks) and text files with characters outside of the ASCII set, or non-textual data (e.g., computer programs, image data) must be transferred using another binary mode.)
$r - Settings
Settings used for transferring data. Included in settings are: 1) Number Data Bits (the number of bits per character); 2) Number Stop Bits (the number of bits to signal the end of a byte); and 3) Parity (the parity checking technique used). The syntax of these elements is:
<Parity>-<Number Data Bits>-<Number Stop Bits>
If only the parity is given, the other elements of settings and their related hyphens are omitted (i.e., <Parity>). If one of the other two elements is given, the hyphen for the missing element is recorded in its proper position (i.e., <Parity>--<Number Stop Bits> or <Parity>-<Number Data Bits>- ). The values for parity are: O (Odd), E (Even), N (None), S (Space), and M (Mark).
$s - File size
Size of the file as stored under the filename indicated in subfield $f. It is generally expressed in terms of 8-bit bytes (octets). It may be repeated in cases where the filename is repeated and directly follows the subfield $f to which it applies. This information is not given for journals, since field 856 relates to the entire title, not to particular issues.
$t - Terminal emulation
Whether terminal emulation is supported. Terminal emulation is usually specified for remote login (first indicator contains value 2 (Remote login (Telnet)).
$u - Uniform Resource Identifier
Uniform Resource Identifier (URI), which provides standard syntax for locating an object using one of the Internet protocols or by resolution of a URN. Field 856 is structured to allow for the creation of a URL from the concatenation of other separate 856 subfields. Subfield $u may be used instead of those separate subfields or in addition to them. Subfield $u may be repeated only if both a URN or a URL or more than one URN are recorded.
$v - Hours access method available
Hours that access to an electronic resource is available at the location indicated in this field. If the record is for a system or service, the hours of availability are recorded in field 307 (Hours, etc.). This subfield is only used to record hours of availability of the specific location indicated in field 856.
$w - Record control number
System control number of the related record preceded by the MARC code, enclosed in parentheses, for the agency to which the control number applies. The data in the subfield links field 856 to the MARC record having the same data in a control number field. See Organization Code Sources for a listing of organization code sources used in MARC 21 records.
$x - Nonpublic note
Note relating to the electronic location of the source identified in the field. The note is written in a form that is not adequate or intended for public display. It may also contain processing information about the file at the location specified.
$y - Link text
Link text used for display in place of the URL in subfield $u. When subfield $y is present, applications should use the contents of it as the link instead of subfield $u when linking to the destination in subfield $u.
Use of the link text is independent of any decision concerning the second indicator value.
$z - Public note
Note relating to the electronic location of the source identified in the field. The note is written in a form that is adequate or intended for public display.
$2 - Access method
Access method when the first indicator value contains value 7 (Method specified in subfield $2).
May include access methods other than the four main TCP/IP protocols specified in the first indicator. The data in this subfield corresponds with the access schemes specified in Uniform Resource Locators (URL) (RFC 1738), a product of the Uniform Resource Identifiers Working Group of the IETF. The Internet Assigned Numbers Authority (IANA) maintains a registry of URL schemes and defines the syntax and use of new schemes. The Library of Congress will include an authoritative list based on that standard in the MARC Code Lists for Relators, Sources, Description Conventions .
$3 - Materials specified
Part of the bibliographic item to which the field applies.
856 42$3Finding aid$u
$6 - Linkage
See the description of this subfield in Appendix A: Control Subfields.
$8 - Field link and sequence number
See the description of this subfield in Appendix A: Control Subfields.


856 with URL/URN:

856 41$u
856 40$u$qtext/html
856 41$u$x
856 1#$u$kguest
856 42$3Finding aid$u
856 42$3French version$u
856 42$3Essays from annual reports$u
856 1#$u$s16874 bytes
856 2#$utelnet://$nUniversity of Maine$t3270
856 1#$u$cdecompress with PKUNZIP.exe$xcannot verify because of transfer difficulty
856 4#$zPart of the Ovid Mental Health Collection (MHC). Follow instructions on MedMenu page for Ovid login.$u
856 40$u$zAddress for accessing the journal using authorization number and password through OCLC FirstSearch Electronic Collections Online. Subscription to online journal required for access to abstracts and full text
856 4#$u$yElectronic resource (JPEG)
856 4#$u$yElectronic resource (PDF)

856 without URL/URN:

856 2#$$b128.101.95.23
856 1#$$cMust be decompressed with PKUNZIP$
856 0#$akentvm.bitnet$facadlist file1$facadlist file2$facadlist file3
856 0#$auicvm.bitnet$fAN2$hListserv
856 2#$$nUniversity of Michigan Weather Underground$p3000
856 10$zFTP access to PostScript version includes groups of article files with .pdf extension$$d/pub/EIS/vol*no*/adobe$f*.pdf$lanonymous$qapplication/pdf


Embedded Holdings Information - When holdings information is embedded in a MARC bibliographic record, multiple occurrences of field 856 may be used if the information does not include other holdings information fields that must be linked to a specific field 856 for intelligibility. Subfield $3 may be used to specify the parts of an item to which information in field 856 applies.
Display Constants - Introductory terms or phrases such as Electronic resource:, Electronic version:, etc. are not carried in the MARC record. They may be system generated as display constants associated with the second indicator value.
Second indicator Display constant
# Electronic resource:
0 Electronic resource:
1 Electronic version:
2 Related electronic resource:
8 [no display constant generated]
Spacing underscore and tilde in URLs - In February 1994, additional characters in the MARC character set were defined to both accommodate existing bibliographic needs and to align it with the ASCII and ANSEL character sets. Both the spacing underscore and the spacing tilde were added at the time because of the need in directory and file names for electronic resources.

Many systems have implemented these characters, however, for systems that have not implemented the spacing underscore and tilde, the following alternative characters may be used:
%5F for spacing underscore
%7E for spacing tilde
Style for Recording Telephone, Numbers - In subfield $b, periods, spaces, and parentheses used to divide the portions of a number are replaced with hyphens. Numbers are recorded as follows:
<country code>-<area/city code>-<exchange/line number>
Exchange/line number portion often includes internal separators which are replaced by hyphens. If an extension is also given, it is appended to the telephone number preceded by a space and " x".
856 3#$b1-202-7072316$j2400/9600$nLibrary of Congress, Washington, DC$oUNIX$rE-7-1$tvt100$zRequires logon and password


$g - Electronic name - End of range [REDEFINED, 1997]
$g - Uniform Resource Name [OBSOLETE, 2000]
Because subfield $g (Electronic name - End of range) was rarely if ever used, it was redefined as Uniform Resource Name in 1997. It was subsequently made obsolete in favor of recording the URN in subfield $u.
$q - File transfer mode [REDEFINED, 1997]
Subfield $q was defined to contain an indication of whether the file was transferred as binary or ASCII. It was redefined to contain type of electronic format.
$u - Uniform Resource Identifier [RENAMED, 2000]
Prior to 1999, subfield $u was defined as Uniform Resource Locator and was repeatable. It was changed to not repeatable because of ambiguity in determining when the subfield could be repeatable. Subfield $u was changed back to repeatable and renamed Uniform Resource Identifier in 2000 to record both URLs and URNs after subfield $g was made obsolete.
$y - Link text [NEW, 2000]

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