Cisco Systems ATA 186 6-19, Possible Causes for Failure, Analysis, Possible Cause for Failure

Chapter 6 Configuring and Debugging Fax Services

Debugging the Cisco ATA 186/188 Fax Services

Possible Causes for Failure

•Fax/modem pass-through option is not enabled on the gateway.

•Fax/modem pass-through NSE payload type are configured differently on the Cisco ATA and the gateway.

Example 6-9 Fax Pass-through Mode Failure

---------- FAX Summary 1			----------
[	37]<2.53=>3.200>	Codec G723
[	39]<3.200=>2.53>	Codec G723
[	143]<3.200=>2.53>	Codec G711u/D
[	144]<3.200=>2.53>	NSE	PT 100,		EVT 192: Up-Speed, CED tone Detected
[ 1602]<3.200=>2.53>		NSE	PT 100,		EVT 192: Up-Speed, CED tone Detected
[ 1604]<2.53=>3.200>		Codec G711u/D
[ 1820]<2.53=>3.200>		NSE	PT	96,	Cisco Fax Relay
[ 1966]<2.53=>3.200>		NSE	PT	96,	Cisco Fax Relay

Analysis

•<2.53> is the originating gateway, and <3.200> is the terminating Cisco ATA.

•The Cisco ATA upspeeds to G.711µ-law and sends G.711 upspeed NSE signaling packets.

•The <2.53> gateway upspeeds to G.711µ-law and then sends Cisco fax relay event packets.

Possible Cause for Failure

•Cisco fax relay option is not disabled on the gateway.

Example 6-10 Fax Pass-through Mode Failure

---------- FAX Summary 1			----------
[	33]<3.200=>2.53>	Codec G729
[	39]<2.53=>3.200>	Codec G729
[	562]<2.53=>3.200>	NTE	PT 101, EVT	34: Modem Mode, ANSam tone Detected (RFC2833)
[	563]<2.53=>3.200>	NTE	PT 101, EVT	34: Modem Mode, ANSam tone Detected (RFC2833)
[	565]<2.53=>3.200>	NTE	PT 101, EVT	34: Modem Mode, ANSam tone Detected (RFC2833)
[	566]<2.53=>3.200>	Codec G711u/D
[	568]<2.53=>3.200>	NTE	PT 101, EVT	34: Modem Mode, ANSam tone Detected (RFC2833)
[	580]<3.200=>2.53>	Codec G711u/D

Analysis

•<3.200> is the originating Cisco ATA, and <2.53> is the terminating gateway.

•Both sides initially use G.729.

•<2.53> gateway sends NTE signaling packets, then upspeeds to G.711µ-law.

•<3.200>The Cisco ATA switches to G.711µ-law also, but never sends NTE signaling packets.

•Fax transmission fails because <2.53> gateway does not receive any NTE packets, and it drops the fax call.

Possible Cause for Failure

•The Cisco ATA does not support the NTE signaling method and requires that the gateways use the NSE signaling method.

Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide for MGCP (version 3.0)

OL-4803-01 6-19