Constant	Meaning
LINEBEARERMODE_VOICE	This is a regular 3.1 kHz analog voice-grade bearer service. Bit integrity is not assured. Voice can support fax and modem media types.
LINEBEARERMODE_SPEECH	This corresponds to G.711 speech transmission on the call. The network can use processing techniques such as analog transmission, echo cancellation, and compression/decompression. Bit integrity is not assured. Speech is not intended to support fax and modem media types.
LINEBEARERMODE_MULTIUSE	The multiuse mode defined by ISDN.
LINEBEARERMODE_DATA	The unrestricted data transfer on the call. The data rate is specified separately.
LINEBEARERMODE_ALTSPEECHDATA	The alternate transfer of speech or unrestricted data on the same call (ISDN).
LINEBEARERMODE_NONCALLSIGNALING	This corresponds to a non-call-associated signaling connection from the application to the service provider or switch (treated as a media stream by TAPI).
LINEBEARERMODE_PASSTHROUGH	When a call is active in LINEBEARERMODE_PASSTHROUGH, the service provider gives direct access to the attached hardware for control by the application. This mode is used primarily by applications desiring temporary direct control over asynchronous modems, accessed through the Win32 comm functions, for the purpose of configuring or using special features not otherwise supported by the service provider.
LINEBEARERMODE_RESTRICTEDDATA	Bearer service for digital data in which only the low-order seven bits of each octet may contain user data (for example, for Switched 56kbit/s service).