Before You Begin; The Auto Callback Screen - ZyXEL Communications ISG50-ISDN User Manual

made from VoIP accounts to emergency dispatchers, but also provide information on the call's
originating number and, usually, location information.
However, this system still has disadvantages over traditional emergency call service. For example,
the physical location provided to the PSAP is usually the account-holder's address as registered with
the VoIP provider; this is not necessarily the location from which the VoIP account is being used.
Furthermore, VoIP emergency calls are subject to the limitations of the Internet connection over
which they are made, which may be unreliable. Also, VoIP services that do not directly connect to
the public telephone network are not required to adhere to the FCC's E911 regulations. Lastly, the
E911 service is available only in North America. Similar systems exist elsewhere in the world, but
regulation and implementation may vary.
For these reasons, the ISG50 routes all calls made to the emergency numbers you configure via its
FXO interface whenever possible. The ISG50 drops an ongoing FXO call if necessary.

34.1.3 Before You Begin

Emergency Calls
Before you configure emergency calling, ensure that you are aware of all local emergency call
numbers used in the location where the ISG50 is to operate. Bear in mind that emergency calls
may be made to phone numbers other than the standard public emergency services number (to a
private security company or medical facility, for example).
Music on Hold
Before you configure music on hold, ensure that the audio file you want to use is compatible with
the standards described in

34.2 The Auto Callback Screen

The auto callback feature is used when a caller encounters a busy signal when dialing one of the
extensions. The caller can then request the ISG50 to automatically call both parties when both of
the extensions are free.
Click Configuration > PBX > Call Service > Auto Callback to configure the auto callback
feature.
Figure 353 Configuration > PBX > Call Service > Auto Callback
ISG50 User's Guide
Section 34.6 on page 539.
Chapter 34 Call Services
533