I've found in some documentation that the resource "Supervisory Disconnect" about calling from FXO to FXO, is always restricted to HCM (high-performance compression modules) to support tone detection (http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t3/dt_fxodt.htm#xtocid3).
Is there any version or feature of IOS that I can utilize the VCM (standard voice compression modules) instead of HCM?
I am running VoIP over FR in a MC3810 with VCM and FXO as shown as follow.
pbx--fxo-3810----wan----3810-fxo--pbx
kind regards ...
