My customer environment is on CCM 7.x with Cisco 2821 as voice gateway and VG224 as fax gateway. There are couple of fax users are receiving blank pages and happened to random customers too.
I have tested with random fax brand like Panasonic, Canon and Brothers, and also unable to negotiate in high speed and seem stable at 4800bps. The incoming line is fiber then converted to coax. How do I troubleshoot such FoIP environment ? Please advise.
The VG224-24FXS is running on IOS 12.4(9)T7. I am attaching the vg224 configuration.
I assume the call is being received by the Cisco 2821 sent to CCM and then redirected by CCM to the VG224? Would be good to show topolgy and call flow path.
Without more info is tough to say what's going on but I *suspect* what is happening is the CCM is attempting to send the call as a FAX relay to the VG224 and the VG224 is currenlty configured for Fax pass through. Try and use FAX relay on the VG224. If you're using recent IOS I believe you can use FAX relay with MGCP or SCCP.
To answer your troubleshooting question, ideally you would need to take an SDI trace on CCM and look at some MGCP debugs when you place a call. This way you find pointers as to what the issue is.
I am new to this. Cisco 2821 and VG224 are configured with MGCP to CCM. The fax flow is as following;
E1 --> C2821 --> CCM 7.x --> VG224 --> Fax machines
How can I know the mode of fax setting on CCM and VG224? How do I look at SDI of CCM for such incidents?
My recommendation is you contact TAC for these type of issues.
You can change the VG224 setup from fax passthrough to fax relay in Cisco Unified Communications Manager. I'm attaching a screen shot taken from CUCM 8.0. CUCM 7.x should be very smilar.
For detailed troubleshooting and debugging please contant TAC. This way your service request will be tracked and resolved in a timely manner.