856 - Electronic Location and Access (R)

Indicators	Subfields

Contains the 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 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 elements vary (subfields $a, $b, $c) and when more than one access method may be used. It is also repeated whenever the electronic filename varies (subfield $f) except when a single intellectual work is divided into different parts for online storage or retrieval.

Indicators

First Indicator - Access method

Contains a value that defines how the rest of the data in the field will be used. The value in this indicator position determines which subfields are appropriate.

#	No information provided	Indicates that no information is provided about the relationship of the electronic resource to the bibliographic item described by the record.
0	Email	Indicates that access is through the Mail Transfer Protocol (MAILTP).
1	FTP	Indicates that access is through the File Transfer Protocol (FTP).
2	Remote login (Telnet)	Indicates that access is through remote login using an application such as Telnet.
3	Dial-up	Indicates that access is through a conventional telephone line.
4	HTTP	Indicates that access is through the Hypertext Transfer Protocol (HTTP).
7	Method specified in subfield $2

Second Indicator - Relationship

Contains a value that identifies the relationship between the electronic resource at the location specified in 856 and the item in the record as a whole.

#	No information provided
0	Resource	Indicates that the 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.
1	Version of resource	Indicates that the location in field 856 is for an electronic version of the resource described by the record. In this case, the item represented by the bibliographic record is not electronic but an electronic version is available.
2	Related resource	Indicates that the location in field 856 is for an electronic resource that is related to the 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.
8	No display constant generated

Subfield Codes

$a	Host name (R)	Contains the 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. The convention for a BITNET address is to add .bitnet.
$b	IP address (NR)	Contains the Internet Protocol (IP) numeric address associated with a host. This data changes frequently and is generated by the system, rather than statically stored.
$c	Compression information (R)	Contains information about the compression of a file, in particular, whether a specific program is required to decompress the file.
$d	Path (R)
$f	Electronic name (R)
$g	Uniform Resource Name (R)	Contains the URN for the electronic resource. A URN provides a globally unique location-independent identifier that can be used for identification of the resource and thus facilitates access to the resource. The content of the subfield includes the initials "urn".
$h	Processor of request (NR)	Contains the username, or processor of the request; generally the data which precedes the "@" in the host address.
$i	Instruction (R)	Contains an instruction needed for the remote host to process a request.
$j	Bits per second (NR)
$k	Password (NR)
$l	Logon (NR)	Contains characters needed to connect (i.e., " logon", " login", etc. to an electronic resource or FTP site. For many general-use File Transfer Protocol servers, access is gained by entering the string "anonymous". An account number required for login may also be indicated. This subfield is used to record general-use logon strings which do not require special security.
$m	Contact for access assistance (R)
$n	Name of location of host in subfield $a (NR)	Contains the full name of the location of the host in subfield $a, including its geographical location.
$o	Operating system (NR)
$p	Port (NR)	Contains the portion of the address that identifies the process or service in the host.
$q	Electronic format type (NR)	Contains an 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. 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.) Electronic format type may be taken from enumerated lists such as registered Internet Media Types (MIME types).
$r	Settings (NR)
$s	File size (R)
$t	Terminal emulation (R)
$u	Uniform Resource Locator (R)	Contains the URL, which provides standard syntax for locating an object using existing Internet protocols. Field 856 is structured to create a URL from separate subfields.
$v	Hours access method available (R)
$w	Record control number (R)
$x	Non-Public note (R)
$z	Public note (R)
$2	Access method (NR)
$3	Materials specified (NR)
$6	Linkage (NR)	Contains data that link pairs of fields that are alternate graphic representations of each other. The subfield contains the tag of an associated field and an occurrence number. A complete description of subfield $6 and guidelines for applying it are provided in the 880 Alternate Graphic Representation section.