Playing a prerecorded audio file

[bradmajors]

While I am making an outgoing telephone call with my Obi110 I would like to play over the telephone a prerecorded audio file.

What is the easiest and simplest way to do this? 

(A method which will produce better quality than just placing the speaker of my audio player up to the microphone of the telephone.  My telephone does not have the option of plugging in a headset.)

[QBZappy]

bradmajors,

If you don't mind using a computer, using a softphone such as Xlite, you can make calls using a headset which is connected to the sound card of the computer. While you are in a call, if you play an audio file it can be heard by the other party.

[bradmajors]

I have tried softphones and have failed.

* Both Sjphone and zoiper softphones stop working when the microphone input is disabled.  Playing a prerecorded audio file while the microphone is enabled results in terrible quality.
* I tried X-lite, but for an unknown reason, X-lite's DTMF tones were not recognized.

Are there any softphones which allow the playback of audio files while the microphone input is disabled?

[Ostracus]

Something like this?