Nortel Networks 6.1 - Manual (Page 238)

238 / Using System features
Compact ICS 6.1 System Coordinator Guide P0603544 02
Direct inward system access (DISA)
Control access to your Norstar system with direct inward system access
(DISA). Access to your Norstar system from the public telephone network
should always be controlled with DISA. If your installer or customer
service representative programs the line used for remote access to answer
a call automatically and wait for a DISA internal number, callers hear a
stuttered dial tone and must enter a Class of Service password before they
are allowed into the system.
Class of Service (COS)
To control the level of telephone service a remote user can access, your
installer can assign a remote filter and remote package to the line used for
remote access. The remote filter restricts the numbers that can be dialed on
the line, and the remote package restricts the use of line pools and the page
feature. To change the restrictions for the line, the user can enter their Class
of Service (COS) password when the system answers with DISA, or can
dial the DISA internal number and enter their Class of Service password.
Maintaining security
To maintain the security of your system, the following practices are
recommended:
• Warn anyone to whom you give the remote access number to keep it
confidential.
• Change Class of Service passwords often.
• Warn anyone to whom you give a Class of Service password to
remember it and not to write it down.
• Remove the Class of Service password of anyone who leaves your
company.