# Setting multiple parameters with a single command

Most MSPP endpoint and channel filters support a command for changing any or all parameters associated with that filter. When using these commands, the application provides a pointer to a structure that specifies appropriate parameters for the filter. For example, an application can use the MSP_CMD_ENCODE_ALL command to change multiple parameters associated with a voice encoder filter by specifying parameters values in a msp_FILTER_ENCODE_ALL_CMD structure.

The following table shows commands available for changing multiple parameters for MSPP endpoint filters:

Filter | Command | Associated structure
RTP full duplex IPv4 | MSP_CMD_RTPFDX_CONFIG | msp_ENDPOINT_RTPFDX_CONFIG
RTP simplex receive IPv4 | MSP_CMD_RTPIN_CONFIG | msp_ENDPOINT_RTPFDX_CONFIG
RTP simplex send IPv4 | MSP_CMD_RTPOUT_CONFIG | msp_ENDPOINT_RTPFDX_CONFIG
RTP full duplex IPv6 | MSP_CMD_RTPFDX_V6_CONFIG | msp_ENDPOINT_RTPFDX_V6_CONFIG
RTP simplex receive IPv6 | MSP_CMD_RTPIN_V6_CONFIG | msp_ENDPOINT_RTPFDX_V6_CONFIG
RTP simplex send IPv6 | MSP_CMD_RTPOUT_V6_CONFIG | msp_ENDPOINT_RTPFDX_V6_CONFIG
T38UDP | MSP_CMD_T38UDP_CONFIG | msp_ENDPOINT_T38UDP_CONFIG
TPKT | MSP_CMD_TPKT_CONFIG | TPKT_ENDPOINT_PARMS

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

The following table lists commands available for changing multiple parameters for MSPP channel filters:

Filter | Command | Associated structure
Jitter | MSP_CMD_JITTER_INIT | msp_FILTER_JITTER_CMD_INIT
T.38 fax | MSP_CMD_FAXRELAY_CONFIG | MSP_FAX_CHANNEL_PARMS
Voice decoder | MSP_CMD_DECODE_ALL | msp_FILTER_DECODE_ALL_CMD
Voice encoder | MSP_CMD_ENCODE_ALL | msp_FILTER_ENCODE_ALL_CMD

When using these commands, an application can change specific parameters without changing others by specifying 0xFFFF for 16-bit parameters or 0xFFFFFFFF for 32-bit parameters for parameters that stay the same. The application specifies new values for the parameters it wants to change.

For example, an application can change the gain level and enable VAD of a voice encoder filter by using the MSP_CMD_ENCODE_ALL filter command. The application can set new values for Gain and VadControl parameters and leave the remaining parameters unchanged by specifying 0xFFFF (or 0xFFFFFFFF).

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