Whenever you run a DP4 program your access is controlled by read and write access levels. When you log in, your access level is set up on the system. However, if you are run DP4 programs from outside the outside the DP4 login (for example from a command prompt), your read and write access levels will be set to 0 as a default. You can change this to any value up to 255 on by editing the Default User Preferences in DFSETUP.
Logging in as DP4 sets your access to 99. Higher access levels are only required for access to the DP4 base dictionary.
On a live system you may want to prevent the users acquiring access level 255 by running outside the system. You can do this by setting the Restrict DP4 from outside menu in the Console/Transaction Logging option of DFSETUP.