A communication system is disclosed that generates call progress tones for a
call.
The communication system is comprised of a calling device and an originating system.
Examples of the calling device include a telephone, a cellular phone, a computer,
and a fax machine. To place a call, the calling device transmits set up messages
to the originating system. The originating system transmits set up messages to
a terminating system to set up the call. The originating system receives acknowledgment
message from the terminating system in response to the set up messages. The originating
system generates a call progress message and transmits the call progress message
to the calling device. The calling device generates a call progress tone based
on the call progress message and plays audible sounds that represent the call progress
tone. By having the calling device generate the call progress tones, the originating
system is advantageously available for other communications.