Technical data

J-2 ISDN Service Providers and Manufacturers 90362-01
In some cases, the SPID number is identical to its full ten-digit DN (the
phone number plus the area code; note that the NetBlazer only uses the
seven-digit phone number for the DN). In other cases, the SPID may be the
Directory Number concatenated with various other strings of digits. How a
SPID number appears depends on the individual implementation by the
telephone company.
DNs and Switches
On a 5ESS switch there is usually one phone number for both B channels.
So, the same phone number can be used to dial both B channels regardless
of which channel is idle.
On DMS100 and NI1 switches, there are two DNs. These two DNs function
like two independent phone lines. For example, say you have the following
two DNs: 555-1111 and 555-2222. If the 555-1111 line is in use and the
555-2222 line is not, an attempt to call the 1111 line will fail (since the
number is busy) but an attempt to call the 2222 line will succeed.
On the NetBlazer LS, the DNs are not really assigned to a particular B-chan-
nel; this means that a call to 555-2222 might appear on bri011 or bri012.
Ordering ISDN Service
When you order ISDN service, the telephone company will provide the
following information:
•
The ISDN switch type
• The ISDN phone number(s)
•
The SPID and DN numbers
Note:
If you move your NetBlazer from one area code to another, you may have to
reset the SPIDs and/or DNs to avoid dialing errors. Check your SPID/DN
to see if it includes a three-digit area code to see if this is necessary.