Overview:
In its current implementation mod-rtac provides holding level call number while in some libraries the item level call number is populated.
We will need to return "Effective call number string" (see attached screenshot) when it is populated in the item record. In this string the next logic is implemented:

• if the item level call number is populated, Effective call number string includes all elements (call number prefix, call number and call number suffix)

• if the item level data is empty, then holding call number (including prefix and suffix) information is populated in Effective call number string.

Also, for location name, mod-rtac should return

• location Discovery display name if it isn't empty or

• location name if Discovery display name isn't filled in

Acceptance criteria:

• Item effective call number string is provided for each item in RTAC response instead of just holding-level call number information

• If effective call number information isn't set (i.e. call number is specified neither on holdings nor on item level), the empty field shouldn't be added

• Location Discovery display name should be returned in RTAC response if it is specified instead of location name