Legacy Document

Inside Macintosh: Devices /

Chapter 6 - Power Manager / Power Manager Reference

Power Manager Dispatch Routines / Controlling the Internal Modem

SetIntModemState

You can use the SetIntModemState function to set some parts of the state of the internal modem.

void SetIntModemState(short theState);

theState

A set of bits you can use to set the modem state. Set bit 15 of this parameter to 1 to set bits in the modem state. Clear bit 15 to 0 to clear bits in the modem state. The modem state bits are described in the preceding function description.

DESCRIPTION

The SetIntModemState function configures some of the internal modem's state information. Currently the only items that can be changed are the internal/external modem selection and the wakeup-on-ring feature.

To change an item of state information, the calling program sets the corresponding bit in the parameter theState. For example, to select the external modem, set bit 4 of theState to 1 and set bit 15 to 1. To select the internal modem, set bit 4 to 1 but set bit 15 to 0.

SPECIAL CONSIDERATIONS

In some PowerBook computers, there is a hardware switch to connect either port A of the SCC or the internal modem to the modem port. The two are physically separated, but software emulates the serial port interface for those applications that don't use the Communications Toolbox. You can check the hasSharedModemPort bit returned by PMFeatures to determine which way the computer is set up.

ASSEMBLY-LANGUAGE INFORMATION

The trap is _PowerMgrDispatch ($A09E). The selector value for SetIntModemState is 15 ($0F) in the low word of register D0. The bit field is returned in register D0.