/mcphas been downloaded into the DSP as shown on the Voice Telephony Service Provider Debugging page. Debug vtsp vofr subframe 3 Another fax relay debug command that is helpful for fax with VoFR and VoATM is debug vtsp vofr subframe 3. This command outputs FRF11 frames that have an Annex D fax relay payload type. There is a significant amount of output from this command even with just one fax relay call, and the hex must be decoded (the FRF11 specification is helpful for hex decoding). Additional Debug Commands To debug T.38 capabilities exchange issues, use the debug cch323 h245 command. 1. To debug DSP message exchanges between applications and the DSP, use these debug commands: debug vtsp all • debug voip ccapi inout • debug hpi all (on the Cisco 5300/2600/3600 and all other voice platforms that use the TI c54x DSPs) • debug nextport vsmgr detail (on the NextPort DSP platforms (Cisco 5400, 5850)) • 2. Fax Analyzers Sometimes it is necessary to go beyond the debugging capabilities of the Cisco voice gateways to resolve fax relay problems. Tools such as protocol analyzers and fax analyzers are used to see what occurs in fax relay operation. Fax analyzers such as the Genoa ChannelProbe/FaxProbe by QualityLogic or the HP Telegra can be positioned between the fax device and the Cisco gateway to capture what occurs. Protocol analyzers such as Sniffer and Domino can be helpful when you need to view the fax relay packets that are exchanged between the routers. The ability to resolve a complex problem sometimes requires a combination of equipment—an analyzer to capture the fax traffic at each fax machine and a protocol analyzer to capture the fax relay packets. A single fax call is placed to reproduce the problem, and then the information is captured from the attached devices for analysis. This diagram shows where in the network this test equipment is placed. Most of the fax analyzers have adequate help screens and documentation to help you determine what