Prosody data communications: API: smdc_line_control_v34

Prototype Definition

int smdc_line_control_v34(struct smdc_line_control_v34_parms *controlp)

Parameters

*controlp

a structure of the following type:

typedef struct smdc_line_control_v34_parms {
	tSMChannelId channel;					/* in */
	enum kSMDCV34LineCtlCmd {
		kSMDCV34LineCtlCmdRetrain,
		kSMDCV34LineCtlCmdRenegotiateUp,
		kSMDCV34LineCtlCmdRenegotiateDown,
		kSMDCV34LineCtlCmdEnablePrimary,
		kSMDCV34LineCtlCmdEnableControl,
		kSMDCV34LineCtlCmdBitrateTx,
		kSMDCV34LineCtlCmdBitrateRx,
	} cmd;							/* in */
	union {
		struct {
			tSM_INT min_bitrate;			/* in */
			tSM_INT max_bitrate;			/* in */
		} bitrate;					/* in */
	} u;							/* in */
} SMDC_LINE_CONTROL_V34_PARMS;

Description

Perform a command on a channel which has been configured for V.34 data communications.

Fields

channel

The channel which has been configured for data communications.

cmd

The control operation to perform. One of these values:

kSMDCV34LineCtlCmdRetrain

Initiate a full retrain procedure on the line, negotiating the best new data rate for the primary channel.

kSMDCV34LineCtlCmdRenegotiateUp

Performs a short renegotiation procedure to increase the data rate on the primary channel. This is typically done when the snr_status parameter of smdc_line_status_v34() is greater than zero.

kSMDCV34LineCtlCmdRenegotiateDown

Performs a short renegotiation procedure to decrease the data rate on the primary channel. This is typically done when the snr_status parameter of smdc_line_status_v34() is less than zero.

kSMDCV34LineCtlCmdEnablePrimary

Switches the modem to transmit on the primary channel. Both originating and answering modem must send this command at the appropriate time, as negotiated by a higher-level protocol. This message is only available on the half-duplex V.34 modem; the full-duplex modem always runs on the primary channel.

kSMDCV34LineCtlCmdEnableControl

Switches the modem to transmit on the control channel. Both originating and answering modem must send this command at the appropriate time, as negotiated by a higher-level protocol. This message is only available on the half-duplex V.34 modem; the full-duplex modem always runs on the primary channel. The half-duplex modem is using the control channel when it first returns control to the user after negotiation.

kSMDCV34LineCtlCmdBitrateTx

Change the bitrate limits on the transmitter.

kSMDCV34LineCtlCmdBitrateRx

Change the bitrate limits on the receiver.

u

bitrate

This field is only valid if the cmd is kSMDCV34LineCtlCmdBitrateTx or kSMDCV34LineCtlCmdBitrateRx.

min_bitrate

The minimum bitrate to negotiate for the primary channel, in bits/second.

max_bitrate

The maximum bitrate to negotiate for the primary channel, in bits/second.

Returns

0 if call completed successfully, otherwise a standard error such as:

• ERR_SM_DEVERR - device error
• ERR_SM_BAD_PARAMETER - configured protocol does not support this command

This function is part of the Prosody data communications API.