Transmission services profile 2 is used with LU type 0. Pacing is supported from the application program to the 3270 LU, but not from the LU to the application program. The only session-control request that can be used is Clear, which resets bracket and pacing states, purges any outstanding requests and responses, and also sets the session sequence numbers to 0. After SESSIONC CONTROL=CLEAR has been posted complete, either the application program or the 3270 LU can attempt to send data; if the optional bracket protocol is being used, the begin-bracket indicator must be set on in the first data request sent after Clear. The Start Data Traffic request is not required or allowed. Only a non-negotiable BIND can be specified to start an LU type 0 session. Cryptography is not allowed.