NETGEAR XM128 ISDN manual Analyzing the Captured Data, EPA Commands, Atct, Atc$

Reference Guide for the Model XM128 ISDN Digital Modem

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 NETGEAR CAPI driver. The NETGEAR CAPI driver communicates with the Model XM128 modem 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.

The commands listed in Table 10-2 determine the kind of protocol data to be captured by the EPA.

Table 10-2.		EPA Commands
AT Command		Description
ATCDn	n = 0	Disables the capture of D channel protocols
	n = 1	Enables the capture of D channel protocols (default)
ATCBn	n = 0	Disables the capture of B channel protocols (default)
	n = 1	Enables the capture of B channel protocols
ATCCn	n = 0	Disables the capture of DTE-DCE interface protocols (default)
	n = 1	Enables the capture of DTE-DCE interface protocols

The EPA starts to capture data when the command ATCT is issued. This capturing process continues until the command ATC$ is issued. The EPA maintains 8 Kbytes RAM as a ring buffer. In case the buffer is full, the earliest data captured is overwritten by the latest data.

Analyzing the Captured Data

To view the analyzed result, use the command ATC$. The relevant AT commands are summarized in Table 10-3.

Table 10-3.	Commands for analyzing captured data
AT Command	Description
ATCT	Clears buffer and starts the embedded protocol analyzer. Captures data
	immediately and starts the timer.
ATC$	Invokes the interpretation function of the embedded protocol analyzer and
	displays the results on the DTE screen.

10-6 Troubleshooting