U
SING
P
ROTOCOL
D
ECODE
Protocol Decode, a diagnostic tool that is a part of your ControlCenter
software, reads, filters, and displays a record of the protocol
information for connections made by your ISDN TA. Your ISDN TA
records all the protocol messages that pass between your ISDN TA,
your computer, the telephone company switch, and the device that you
are connecting to.
Note: Protocol Decode does not report information on connections as
they are happening. Instead, it displays information stored on your
ISDN TA from past connections.
To use Protocol Decode, open ControlCenter and click the Protocol
Decode icon. The screen shown in Figure 10-1 appears.
Figure 10-1 “Protocol Decode” screen
Options in the Protocol Decode application include:
ISDN Signaling – Your ISDN TA tracks protocol information on
your ISDN line’s D-channel. If a check mark appears in the box
next to an item, that sort of information is displayed.
“Raw data” displays all the signaling messages passed along your
ISDN line’s D-channel without decoding them.
“Q.921” displays messages interpreted by the Q.921 protocol.
“Q.931” displays messages interpreted by the Q.931 protocol.
Physical Interface – The check boxes in this section allow you to
review activity at the physical layer of your ISDN line and on-
hook and off-hook activity on your ISDN TA’s Analog Device
Ports.