The LINEMEDIAMODE_ constants describe media modes (the data type of a media stream) on calls.


A media stream exists but its mode is not currently known and may become known later. This would correspond to a call with an unclassified media type. In typical analog telephony environments, an inbound call's media mode may be unknown until after the call has been answered and the media stream has been filtered to make a determination.

If the unknown media-mode flag is set, other media flags may also be set. This is used to signify that the media is unknown but that it is likely to be one of the other selected media modes.


The presence of voice energy on the call, and the call is treated as an interactive call with humans on both ends.


The presence of voice energy on the call and the voice is locally handled by an automated application.


A data modem session on the call.


A group 3 fax is being sent or received over the call.


A TDD (Telephony Devices for the Deaf) session on the call.


A group 4 fax is being sent or received over the call.


Digital data is being sent or received over the call.


A teletex session on the call. Teletex is one of the telematic services.


A videotex session on the call. Videotex is one the telematic services.


A telex session on the call. Telex is one of the telematic services.


A mixed session on the call. Mixed is one of the ISDN telematic services.


An ADSI (Analog Display Services Interface) session on the call.


The media mode of the call is VoiceView.

All 32 bits are reserved.

Note that bearer mode and media mode are different notions. The bearer mode of a call is an indication of the quality of the telephone connection as provided primarily by the network. The media mode of a call is an indication of the type of information stream that is exchanged over that call. Group 3 fax or data modem are media modes that use a call with a 3.1 kHz voice bearer mode.

For backward compatibility, it is the responsibility of the service provider to examine the negotiated API version on the line, and to not use this LINEMEDIAMODE_ value if not supported on the negotiated version.

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