That is not correct about FXO in general. What the OP needs is called answer supervision and should be provided by telco. Combined with proper configuration, IOS level, etc. on Cisco side this should work fine. Here is some info about answer supervision on Cisco gear:
You will find that in most countries outside N.A. no additional services for analog lines are available from telco. Meaning, no ground start, no answer supervision, tone-only based disconnect supervision, no analog DID.
In general, my replies are adapted to the region I recognize the OP coming from, so in this as in many other cases, no digital lines = no love.
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...