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Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide for MGCP (version 3.0)
OL-4803-01
Chapter 6 Configuring and Debugging Fax Services
Debugging the Cisco ATA 186/188 Fax Services
Example 6-3 Fax Pass-through Mode
---------- FAX Summary 1 ----------
[ 37]<3.200=>2.53> Codec G723
[ 41]<2.53=>3.200> Codec G723
[ 136]<3.200=>2.53> Codec G711u/D
[ 137]<3.200=>2.53> NSE PT 100, EVT 192: Up-Speed, CED tone Detected
[ 140]<2.53=>3.200> Codec G711u/D
Analysis
• Both sides initially use G.723.
• <3.200> switches to G.711µ-law using a dynamic payload type.
• NSE signaling packets are sent from <3.200>.
• <2.53> switches to G.711µ-law using a dynamic payload type.
Example 6-4 T38 Fax Relay Mode
---------- FAX Summary 1 ----------
[ 15]<2.53=>3.99> Codec G711u
[ 486]<3.99=>2.53> Codec G711u
[ 1277]<3.99=>2.53> Codec T38
[ 1278]<2.53=>3.99> Codec T38
Analysis
• Both sides initially use G.711µ-law.
• Both sides switch to T.38
Example 6-5 Cisco Fax Relay
---------- FAX Summary 1 ----------
[ 8]<2.53=>3.99> Codec G711u
[ 248]<3.99=>2.53> Codec G711u
[ 798]<2.53=>3.99> NSE PT 96, Cisco Fax Relay
[ 799]<3.99=>2.53> NSE PT 97, EVT 192: Up-Speed, CED tone Detected
[ 800]<2.53=>3.99> NSE PT 97, Cisco Fax Relay ACK
[ 801]<2.53=>3.99> Codec C_FxRly
[ 803]<3.99=>2.53> NSE PT 96, EVT 192: Up-Speed, CED tone Detected
[ 804]<2.53=>3.99> NSE PT 97, Cisco Fax Relay ACK
[ 805]<3.99=>2.53> Codec C_FxRly
Analysis
• Both sides initially use G.711µ-law.
• NSE signaling packets are sent between <2.53> and <3.99>.
• Both sides switch to Cisco fax relay.
Using rtpcatch to Analyze Common Causes of Failure
The following examples show the rtpcatch output of failed fax sessions. <3.200> is ATA; <2.53> is a
Cisco gateway.