# DS0 full duplex endpoint filter

Provides an entry and exit point for duplex voice and fax data at the PSTN interface. For information about DS0 endpoint filter parameters, refer to DS0 endpoint address structure and DS0 endpoint parameter structure, and to the mspdef.h header file.

#### Filter ID

MSP_ENDPOINT_DS0

#### Initialization structure

DS0_ENDPOINT_PARMS

#### Restrictions

Used for duplex and simplex voice connections and T.38 fax connections.

#### Channel connections

Allowed connections include:

- Full duplex voice channels

- Simplex voice channels

- Full duplex T.38 fax channels

#### Commands

DS0 full duplex endpoint filters respond to the following command any time after the endpoint is created:

Command ID | Description
MSP_CMD_DS0_CONFIG | Sends a DS0_ENDPOINT_PARMS structure for a particular endpoint filter. The structure specifies whether the endpoint transmits data in voice or fax transmission mode (set to voice by default).

When sending MSP_CMD_DS0_CONFIG commands to DS0 endpoint filters, include a pointer to the following structure:

typedef struct tag_DS0_ENDPOINT_PARMS{
DWORD size
MSP_MEDIA media;
} DS0_ENDPOINT_PARMS;

The MSP_MEDIA parameter is defined as an enumerated data type where MSP_VOICE is the first defined (0) value, and MSP_FAX is the second (1) value.

For a list of command IDs and their associated structures, refer to the mspcmd.h or mspinit.h header files.

#### Queries

None.

#### Unsolicited events

None.

#### Details

Use DS0 endpoint filters to send data to and receive data from PSTN networks. DS0 endpoints are used in both T.38 fax and voice connections.

The following illustration shows a DS0 endpoint filter:

#### See also

RTP IPv4 full duplex endpoint filter, RTP IPv6 full duplex endpoint filter, T.38 fax relay channel filter, Voice decoder channel filter, Voice encoder channel filter