Se utilizaran los siguientes link para realizar un resumen :
http://www.cisco.com/en/US/docs/ios/12_3/vvf_c/cisco_ios_fax_services_over_ip_application_guide/fxappdoc.html
troubleshooting :
http://www.cisco.com/en/US/tech/tk652/tk777/technologies_tech_note09186a0080114565.shtml#topic3-6
http://docwiki.cisco.com/wiki/Cisco_IOS_Voice_Troubleshooting_and_Monitoring_--_Fax_Call_Flow
configuracion :
https://www.cisco.com/en/US/docs/ios/12_1t/12_1t3/feature/guide/dt_t38fx.html
comandos de referencia :
http://www.cisco.com/en/US/docs/ios/12_2/voice/command/reference/vrf_r.html#wp1028033
