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Real Time Availability Checking (RTAC)

If included in your institution's EBSCO Discovery Service (EDS) subscription, you may see up-to-date information that advises you of the availability of a resource within the library.

Real Time Availability Checking (RTAC) advises the user of:


  • Available
  • In Library Use
  • On Hold
  • Checked Out
  • Missing
  • Lost

If your library is part of a library group, you will also be advised of the specific location of an item within the group of libraries.


RTAC and your Custom Catalog Database

RTAC displays within EDS or OPAC on the EBSCOhost interface. If your institution has a z39.50 server or REST service enabled, RTAC can be setup to display holdings information for items in your Custom Catalog in real time. RTAC will display the location, call number, status, and due date of the item. Results from RTAC are displayed within the brief records on the Result List page.

RTAC example

RTAC results will also display on the Detailed Record page within the Catalog Holdings table. Below is an example of RTAC results when an item is available in the library.

RTAC example

Below is an example of RTAC results when an item is not available or is checked out.

RTAC example

If RTAC is unable to return results for any reason, location and call number information will be displayed from the static MARC record. Below is an example of the Catalog Holdings information that displays on the Detailed Record page when RTAC is either not enabled or cannot return results.

RTAC example


Customizing RTAC Column Headings for Catalog Holdings

Using EBSCOadmin, administrators can customize the RTAC column headings for their EBSCO Discovery Service catalog holdings. This can be useful if you would like to add specific labels to headings to make them consistent with what is already being used at your institution.

To customize catalog headings:

  1. Log into EBSCOadmin at

  2. From the Customize Services tab, select the EDS profile for which you would like to customize the catalog headings from the Choose Profile drop-down menu.

  3. Click the Viewing Results sub-tab.

  4. Click the Modify link for Customize Catalog Holdings Table Headings.

  5. Make your changes to the desired column heading fields:

    • Catalog Holdings Table Headings for - Select a catalog from the drop-down menu (If multiple catalogs are available.)

    • Heading Label - Select a language from the drop-down menu.

    • Location - Enter a heading for the location column. (e.g. Your Local Library)

    • Call No. - Enter a heading for the catalog number column. (e.g. Shelf Label)

    • Status - Enter a heading for the status column. (e.g. Materials status, Availability)

    • Due Date - Enter a heading for the due date column. (e.g. Materials Due By)

    • Locations Searched - Enter a heading for the locations searched column. (e.g. Libraries Searched)

    • Other Locations - Enter a heading for the other locations column. (e.g. Other Libraries with this Item)

    • Apply Changes to - If desired, select to apply your changes to ALL catalogs on that profile -OR- apply your changes to ALL profiles with catalogs.

  6. Click Submit to save your changes.


RTAC using z39.50 in a Custom Catalog

RTAC connection to z39.50 server

If your institution has a z39.50 server enabled, the RTAC service can connect to it using the login values that you provide in the Catalog Questionnaire; i.e. address, port number, database name, and optional username/ password. RTAC will use the unique identifier within your static MARC records to find the same record in your z39.50 server. If a record is found, RTAC will display the holdings information in real time within your catalog records.

Record formats - USMARC or OPAC

Depending on your institution’s ILS vendor, the record syntax may be in USMARC or OPAC format. Below is an example of a Z39.50 record in OPAC format. In this example, the 001 field is the indexed field within the z39.50 server that allows RTAC to retrieve it.

The holdings information for each item is at the bottom of the retrieved record.

Z39.50 Record in OPAC format

If your z39.50 server supports USMARC format, the holdings information will usually be found in the 8xx or 9xx fields. RTAC can be configured to retrieve this information from the subfields that contain the location, status, call number, and due date.

Below is an example of a 926 field from a Z39.50 record in USMARC format.

926 $a SPEC-COLL $b Not Checked Out $c PN200.9 .N45 L4 1996 $d BOOK $e Due: 5-18-2010


Setting up RTAC Translations for Records in USMARC Format

Translation tables allow RTAC to display expanded Location and Status messages to your patrons instead of only the abbreviated codes which are difficult to read.

EBSCO’s RTAC service retrieves the exact information within your z39.50 server. Depending on the ILS vendor, the z39.50 server may only support USMARC format. If this is the case, it is likely your Catalog Holdings field will require some extra formatting in order to display the location and status text in the same format as your OPAC.

This requires creating holdings translation tables for both the abbreviated locations and status.

Creating a Holdings Translation Table

Here are the 5 steps for creating the holdings translation table:

  1. Identify a record’s holdings information within your z39.50 server. Usually this can be found in the 900 fields.

    Example: 926 $a MLIB $b CHECKEDOUT $c PN200.9 .N45 L4 1996 $d BOOK $e 5-18-2010

  2. Identify the subfields that contain the abbreviated information. (Usually $a for Location and $b for Status information.)

    Example: 926 $a MLIB $b CHECKEDOUT $c PN200.9 .N45 L4 1996 $d BOOK $e 5-18-2010

  3. Export one table containing all Location abbreviations and a second table for Status abbreviations.

    For instructions on the process of exporting this information you may want to contact your ILS. Note: It may be possible to combine steps 3 and 4.

    Table 1
    Location Code 926 $a


    Table 2
    Status Code 926 $b


  4. In both tables please provide the appropriate translations for your Locations and Status.

    Table 1
    Location Code 926 $a Location for Display
    MLIB Main Library
    SPEC-COLL Special Collections Library


    Table 2
    Status Code 926 $b Status for Display
    CHECHEDOUT Checked Out
    OVRZ Oversize
    BIOGRAPHY Biography Collection


  5. Submit the tables to an EBSCO representative to update your Catalog Holdings field. (



If your institution uses a firewall, you will need to allow EBSCO to access your z39.50 server to setup RTAC for your Custom Catalog database. In order to make sure that access to the RTAC service is uninterrupted, please add the following EBSCO IP address range to your firewall:

IP Details with Wild Card notation

You should open your z39.50 server’s specific port number in order to allow RTAC to connect to it. If you are not sure what your port number is, please contact your ILS vendor.