There are three parts in System Log. Syslog, E-mail and Log Setting.

Syslog

Enable Syslog: If check the box, Syslog will be enabled.
Syslog Server: In addition to the standard event log, the RV082 can send a detailed log to an external Syslog server. Syslog is an industry-standard protocol used to capture information about network activity. The RV082 Syslog captures all log activity and includes every connection source and destination IP address, IP service, and number of bytes transferred. Enter the Syslog server name or IP addres in the Syslog Server field. Restart the RV082 for the change to take effect.

E-mail

Enable E-Mail Alert: If check the box, E-Mail Albert will be enabled.
Mail Server: If you wish to have any log or alert information E-mailed to you, then you must enter the name or numerical IP address of your SMTP server. Your Internet Service Provider can provide you with this information.
Send E-mail To: This is the E-mail address to which your log files will be sent. You may leave this field blank if you do not want to receive copies of your log information.
Log Queue Length (entries): The default is 50 entries. RV082 will e-mail log when Log entries is over 50.
Log Time Threshold (minutes): The default is 10 minutes. RV082 will e-mail log every 10 minutes.
RV082 will e-mail log when meet any one of Log Queue Length or Log Time Threshold settings.   
E-mail Log Now: Clicking E-mail Log Now immediately send the log to the address in the Send E-mail to Filed.

Log Setting

Alert Log
Check the following events box for receiving alert log. Syn Flooding, IP Spoofing, Win Nuke, Ping of Death and Unauthorized Login Attempt.
General Log
Check the following events box for receiving log. System Error Messages, Deny Policies, Allow Policies, Content Filtering, Data Inspection, Authorized Login, Configuration Changes.

There are four buttons follow the setup section.

View System Log: Once you press this button, the new window will pop up System Log.
Outgoing Log Table: Once you press this button, the new window will pop up and show you the outgoing packet information including LAN IP, Destination URL/IP and Service/Port number.
Incoming Log Table: Once you press this button, the new window will pop up and show you the incoming packet information including Source IP and Destination Port number.
Clear Log Now: This button will clear out your log without E-mailing it. Only use this button if you don't mind losing your log information.