The TRANSMIT command allows several different specifications of a list of addressees. The simplest is a single addressee whose node name and user ID are specified explicitly. The next level is the nickname specification. The nickname is a 1 to 8 character name that is a synonym for the node and user ID. The TRANSMIT and RECEIVE commands find the actual node and user ID by looking up the nickname in tables provided in the NAMES data set. The final level of addressing is a distribution list. A definition in the NAMES data set identifies a distribution list name. The named list can reference up to 100 nicknames of either addressees or other distribution lists.

Each user of the TRANSMIT and RECEIVE commands can have one or more NAMES data sets to resolve nicknames and establish the default mode of operation. In the absence of any explicit installation specification, the name of the first of these data sets is ‘prefix.NAMES.TEXT’. The first data set contains the names of any other NAMES data sets. The data set can have either fixed or varying length records. Using varying length records will save disk space. The records are numbered according to standard TSO/E conventions. They can also be unnumbered. The data set is either blocked or unblocked with any record length less than or equal to 255.

The data set is composed of two sections, the control section and the nicknames section. The control section must precede the nicknames section. The control section ends at the first :NICK tag. Use the control section to set defaults for LOG/NOLOG and NOTIFY/NONOTIFY, prolog or epilog lines, the default log data set name, and to identify other NAMES data sets that are used.

The nicknames section contains one entry for each nickname and distribution list name that you want to define.

Each occurrence of a colon in the NAMES data set is treated as the start of a tag. If the tag following the colon is not one of those described later in this section, it is treated as a user-defined tag that may be processed by an installation-written application that uses the NAMES data set. The information that follows a user-defined tag is ignored by TRANSMIT and RECEIVE processing. For more information about installation-written applications, see z/OS TSO/E Programming Guide.