Справочное Руководство для Netopia 430 s

Calling number authentication (CNA), an application of caller ID, is a 
method of verifying that an incoming call is originating from the 
expected site. Using CNA, you can increase the security of your 
network by requiring that callers not only possess the correct PAP or 
CHAP information, but also that they are calling from a par ticular 
physical location. 

CNA works by checking the calling number that the Netopia ISDN 
Router receives during the initial setup phase of an incoming call 
against a set of stored numbers. Each number in the stored set is 
defined in a specific connection profile. When a match occurs, the 
incoming call is handled by the connection profile containing the 
matched number.

Using CNA can also provide cost savings because calls are not 
billed during the CNA phase. With CNA, a caller can set up a 
connection to the Netopia ISDN Router without incurring any 
charges by accessing a dial-back connection profile. If the caller’s 
rates are higher than those charged to the Netopia ISDN Router’s 
return call, then using CNA has saved the difference.

CNA should be available where caller ID ser vices are available, but 
consult with your ISDN ser vice provider to find out if your ISDN line 
is provisioned for caller ID.

Also note that if the calling side has instructed the phone company 
to block deliver y of its caller ID, the answering side will not be able 
to authenticate.

If you have a Nor thern Telecom DMS-100 line (either custom or NI-1) 
you should verify that the line suppor ts "Calling Number Deliver y" 
ser vice.

If your line is an AT&T 5ESS (either custom or NI-1) verify that it 
suppor ts "CPN/BN (Calling Par ty Number/Billing Number) Deliver y" 
ser vice. 

If your line does not suppor t the appropriate ser vice, CNA may not 
work properly.