A logon mode is a set of session protocols expressed as a string of characters called session parameters. These session parameters describe how the session is to be conducted in terms of data compression, data encryption, pacing, class-of-service, RU size, and so on. A logon mode table contains definitions for one or more logon modes.

VTAM® has an IBM-supplied logon mode table named ISTINCLM that provides generally accepted session protocols for a basic list of IBM® device types. You can define a supplemental logon mode table, and you can then associate it with a logical unit by specifying the table's name in the MODETAB operand of the logical unit's definition statement.

For more information about implementing a logon mode table, see the z/OS Communications Server: SNA Resource Definition Reference. The default logon mode table is found in the z/OS Communications Server: SNA Resource Definition Reference.