Cisco Systems ATA 186, ATA 188 Using prserv for Diagnosing Fax Problems, prserv Overview, Action

Chapter 6 Configuring and Debugging Fax Services

Debugging the Cisco ATA 186/188 Fax Services

Table 6-1 Solving Common Fax Problems (continued)

Problem	Action
The Cisco ATA is not	For fax mode, the AudioMode configuration parameter should be set to
configured for fax mode or	0xXXXX0012 (X = value not applicable) for the Phone 1 port of the
fax pass-through mode.	Cisco ATA, and 0x0012XXXX for the Phone 2 port.
	For fax pass-through mode, AudioMode should be set to 0xXXXX0015
	for the Phone 1 port of the Cisco ATA, and 0x0015XXXX for the Phone
	2 port.
The remote gateway is not	When the Cisco ATA is configured for fax pass-through mode, all remote
configured for modem/fax	gateways must be configured with modem/fax pass-through mode either
pass-through mode.	on a dial-peer level or system level.
Fax relay is not disabled	Fax relay is enabled by default on some Cisco gateways. When fax relay
on the remote gateway.	is enabled, it can override fax pass-through mode and cause fax failure.
	Examples of the CLI commands to disable fax relay for IOS gateways are
	as follows:
	• fax rate disable for H.323/SIP gateways
	• mgcp fax t38 inhibit for MGCP gateways
Fax/modem pass-through	Some Cisco gateways (such as Cisco VG248, and Cisco 6608) may use
method on the remote	signaling messages based on RFC2833 for G.711 upspeed when loaded
gateway is not compatible	with older software images. This method is incompatible with the Cisco
with the Cisco NSE-based	NSE-based method.
method.	You must check to make sure that the image on your gateway supports the
	Cisco NSE-based fax/modem pass-through. Otherwise, you must
	configure the Cisco ATA to use fax mode.
NSE payload types differ	The Cisco ATA has a configurable NSE packet payload-type value whose
between gateways.	default is 100. This value is compatible with the implementations of most
	Cisco gateways. However, some Cisco gateways use 101 as the NSE
	payload type.
	Ensure that all gateways in your environment use the same NSE payload
	type if you wish to successfully use fax pass-through mode.

Using prserv for Diagnosing Fax Problems

This section contains the following topics:

•prserv Overview, page 6-8

•Analyzing prserv Output for Fax Sessions, page 6-9

prserv Overview

prserv is a tool that runs on a Microsoft Windows-based PC and serves as a log server that captures debug information that the Cisco ATA sends to your PC IP address/port. The debug information is saved into a readable text file.

To enable your Cisco ATA to send debug information, you need to set the NPrintf configuration parameter to your PC IP address and an available port, as shown in the following procedure:

Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide (SCCP)

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