# T38 fax relay channel parameter structures

When an application creates an MSPP API T38UFP fax channel, it must specify the following parameters:

typedef struct tag_MSP_FAX_CHANNEL_PARMS
{
DWORD size;
msp_FILTER_FAXRELAY_CONFIG FaxRelayParms;
} MSP_FAX_CHANNEL_PARMS;

## MSP_FAX_CHANNEL_PARMS

#### Dependent function: mspCreateChannel

Field | Type | Default | Units | Description
size | DWORD | N/A | N/A | Size of the parameter structure.
msp_FILTER_FAXRELAY_CONFIG | Structure | N/A | N/A | Structure specifying parameters for fax modem functionality.

## T.38 fax relay configuration channel parameter structure

When an application creates an MSPP API T.38 fax channel, it must specify the following parameters:

typedef struct tag_msp_FILTER_FAXRELAY_CONFIG
{
WORD modemask;
WORD eventmask;
WORD maxbitrate;
WORD timeout;
} msp_FILTER_FAXRELAY_CONFIG;

## msp_FILTER_FAXRELAY_CONFIG

#### Dependent function: mspCreateChannel

Field | Type | Default | Units | Description
modemask | WORD | NSF enabled (ECM disabled) | N/A | Enables and disables specific T.38 fax features. The following values are defined: FAXRELAY_MODEMASK_DEFAULT FAXRELAY_MODEMASK_DISABLE_NSF_FILTERING FAXRELAY_MODEMASK_DISABLE_ECM FAXRELAY_MODEMASK_ENABLE_NON_STD_T38_ECM
eventmask | WORD | All enabled | N/A | Specifies the unsolicited events that are passed back to the application. The following values are defined: FAXRELAY_EVENTMASK_DEFAULT Reports no fax session information. FAXRELAY_EVENTMASK_REPT_FAX_BEGIN_END Reports the beginning and ending of a fax session. FAXRELAY_EVENTMASK_REPT_PASSED_PAGE Reports successful passing of a fax page.
maxbitrate | WORD | 14400 | Bits/s | Maximum bit rate of the fax transmission (in bits/sec). FAXRELAY_MAXBITRATE_DEFAULT FAXRELAY_MAXBITRATE_14400 FAXRELAY_MAXBITRATE_9600 FAXRELAY_MAXBITRATE_4800 FAXRELAY_MAXBITRATE_2400 FAXRELAY_MAXBITRATE_DISABLE_FILTER
timeout | WORD | 15000 ms. | ms | Fax session timeout value. The following constants are defined for this parameter: FAXRELAY_TIMEOUT_DEFAULT FAXRELAY_TIMEOUT_MIN (0 ms.) FAXRELAY_TIMEOUT_MAX (65000)

Note: Switching channels have no associated parameters.