104
The D-channel signaling protocols include layer 2 and layer 3 call
control protocols. Frames and messages exchanged via the D-
channel are all recorded for further analysis. These data messages are
essential to understanding interactive operations between an ISDN
TA and the ISDN network. They contain the compatibility
information for the Omni TA128 and your Central Exchange.
The B-channel user data protocols include X.75 and V.120. Only the
layer 2 header (addresses and control bytes) and layer 3 header are
captured. Since X.75 may be used with various layer 3 protocols
(e.g. T.70, T.90, and ISO8208), only the first 8 octets of the
information field are recorded as the layer 3 header, and are displayed
in raw data form. The analysis of the protocol data will be carried out
by ZyXEL’s Technical Support department.
The DTE-DCE protocols (at the R reference point according to the
ISDN nomenclature) include the AT commands/responses as well as
the CAPI internal interface. The CAPI internal interface is used with
the ZyXEL CAPI driver. The ZyXEL CAPI driver communicates
with the Omni TA128 through this internal interface. It is not
recommended that users get involved in this internal interface. The
AT commands/responses, on the other hand, are in a standard user
interface. An analysis of these commands and responses might prove
very informative. All messages captured by the EPA are tagged with
a time stamp according to a free running timer that starts at the
beginning of data capture. The resolution of this timing information is
in 0.01 second intervals.
The following commands determine the kind of protocol data to be
captured by the EPA:
AT Command
Description
ATCDn
CD0
Disable the capture of D-channel protocols
CD1
Enable the capture of D-channel protocols
(default)
ATCBn
Summary of Contents for Omni TA128
Page 1: ...Omni TA128 User s Manual Version 2 0 ZyXEL ACCESSING INTERNET INTRANET...
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Page 136: ...124 Command Options Function Description Ref VC View the Call back Number table...
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