I have a customer that would like to use 2x FXO card as backup to there ISDN
My simple thinking would be to use a H323 GW trunk the FXO and ISDN and use the preference command to make use that the ISDN is always tried as a first choice. Unless there is an advantage in using MGCP with Route list, Route Groups... ?
The customer has also added two more requirements which are not meet by the above solution
1) They would like the FXO lines to be used only when the ISDN is down
2) When the FXO is been used, 3 designated phone's get priority over all others
The first requirement I don't think can be done. The second I am not sure. Any ideas, suggestions?