Some implementations allow for either delivery mechanism to be used. The CTI approaches described as first party and third party are call control rather than media control mechanisms. These approaches cover functions that deal with the making, transferring and clearing of calls. CTI of this sort does not concern itself with the content of the calls. The computer may be mediating voice, data or even video calls, it makes little difference in so far as call control is concerned.
Media control is more concerned with moving calls and messages between different media resources.
Within a PC the media resource may be a fax processing card or a speech recognition card or perhaps a speech synthesis card. The control required here concerns the manipulation of the media resource rather than routing calls to that resource. For example, a call may be routed to a speech recognition resource. The controls required to deal with that resource would concern the setting of thresholds of accuracy, the downloading of vocabularies and the receipt of recognition codes. In the messaging world, the controls required would be exemplified by commands such as record, play and rewind.