ZyXEL Communications ISG50 User Manual

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 Chapter 34 Call Services
ISG50 User’s Guide
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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