Apparently the latest rage in India is background tones.Â The moral equivalent of the desktop wallpaper on your PC, these are background sounds played while you’re having a telephone conversation with another person.Â They’re one of a whole class of new services which are implemented using media handling in the network. Other services like background tones might include:
- whispered announcements of callers.Â Instead of the call waiting tone, how about an announcement of who’s calling, which only you can hear?
- in-call digit detection.Â Many conference bridges allow you to use handset digits to control the call — mute channels, create sidebar conferences and the like.Â New in-call services could also be created for consumers.Â How about a special key combination to query the switch, and ask how long the call has been in progress?
The problem with all of these is that they require the media portion of the call to pass through a media server.Â SIP proxies are cheap and can handle many many callers because they do not handle media.Â Â Like air traffic controllers, they simply tell the planes, or in this case the bits, where to go.Â Â In comparison,Â Â media servers are not cheap.Â Media servers are like the airports — processing the passengers, refueling the aircraft,Â handling border control and so on. This is where the expense in air travel is.Â And, on a telecom network, the most expensive call handling component is the media server.
Passing every call through a media server, which is what happens with background tones, therefore drives the cost of the call up.Â Hopefully, the revenue from the background tone service is enough to make up the difference.