These are derived from attributes of TYPE=TERMINAL macros, which are often identical for many terminals.
They are put into the CSD group named in the TYPESGROUP parameter. If no TYPESGROUP is specified, they are put in the group currently being created, with the TERMINAL definitions.
The “typeterm” attributes of each TYPE=TERMINAL table macro are checked with existing TYPETERM definitions and if they do not match any of these, a new TYPETERM is added to the CSD file.
For this reason, it is a good idea to use the TYPESGROUP parameter to avoid creating duplicate TYPETERMs in different groups. It is convenient to keep the TYPETERMs in a separate group anyway.
TYPETERMs created on the CSD file during the migration are named systematically, in a way related to the TRMTYPE parameter of the original terminal definition. The name consists of a prefix (of 3–5 characters) with a 3-character suffix.
For example, a TYPETERM defining attributes for a 3270 printer is named 3270P001. Variants with the same TRMTYPE are named 3270P002, and so on. The migration process ensures that this name is used as the TYPETERM parameter of every TERMINAL definition that references it.
Migration may produce some TYPETERM names that would be incomprehensible to those who have to use them when defining terminals. You can later rename such TYPETERMs using the RDO command RENAME, and ALTER the TERMINAL definitions that refer to them. The naming rules for TYPETERM identifiers are given in TYPETERM definition attributes.