Interphase Tech 5536 Benutzerhandbuch

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Watching ISDN Ports and Channels
142
Interphase Corporation
• Fourth 
level: Channels available on a port
Each PRI port has one ISDN D channel. Each PRI port 
also has 23 ISDN channels (North America, Japan) or 
30 ISDN B channels (Europe, Australia). The digital 
modem port has as many channels as there are digital 
modems configured on the board.
Watching ISDN Ports and Channels
The ISDN D channel is generally used to transmit signalling 
frames, such as call in progress, incoming call, or call 
accepted. Watching this channel provides diagnostic 
information about the ISDN connection phase. For example, if 
a RAS connection fails (during either dial-in or dial-out), the 
first channel to watch is the ISDN D channel.
ISDN B channels transmit data frames after an ISDN 
connection is established. The first few data frames exchanged 
between local and remote sites correspond to a second 
connection phase to allow the establishment of the upper layer 
(for example, the PPP protocol).
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Before establishing a call, you cannot know which ISDN B 
channel will be used. Therefore, to be sure to capture call 
data, you must activate traces for all the ISDN channels.
To activate watching on one channel, select that channel in the 
configuration panel of the SynWatch dialog box. To activate 
watching on all of a port’s channels, select the port in the 
configuration panel. Use the left or right mouse button as 
follows to start or change watch activity: