On the Octel, there is a feature called Online CDR Utility. Go to menu 20.4.2 Put in a date range and the mailbox you are checking on. Once selected, select the P option.
The system will now being to display all logs related to that mailbox. When the system sends a page, it generates a OC log. I use this all the time if a user complains about not getting a page right after setting this up. If the log is missing, it means the user forgot to enable Outcall Notification or didn't setup their paging schedule correctly. The log will even tell you if it got a busy or other issue.
For the full details regarding all the logs, search Avaya's support site for Online CDR. The appendix of the guide will give you all the details about the log entries.