Inside Macintosh: Devices /

Chapter 6 - Power Manager / Power Manager Reference

Power Manager Dispatch Routines / Controlling the Internal Modem

GetIntModemInfo

You can use the GetIntModemInfo function to find out information about the internal modem.

unsigned long GetIntModemInfo();

DESCRIPTION

The GetIntModemInfo function returns a 32-bit field containing information that describes the features and state of the internal modem. It can be called whether or not a modem is installed and will return the correct information.

If a bit is set, that feature or state is supported or selected; if the bit is cleared, that feature is not supported or selected. Undefined bits are reserved by Apple for future expansion.

Bit name	Bit number	Description
hasInternalModem	0	An internal modem is installed.
intModemRingDetect	1	The modem has detected a ring on the telephone line.
intModemOffHook	2	The internal modem has taken the telephone line off hook (that is, you can hear the dial tone or modem carrier).
intModemRingWakeEnb	3	The computer will come out of sleep mode if the modem detects a ring on the telephone line and the computer supports this feature (see the canWakeupOnRing bit in PMFeatures).
extModemSelected	4	The external modem is selected (if this bit is set, then the modem port will be connected to port A of the SCC; if the modem port is not shared by the internal modem and the SCC, then this bit can be ignored).

Bits 15-31 contain the modem type, which can have one of the following values:

Value	Meaning
-1	Modem is installed but type not recognized.
0	No modem is installed.
1	Modem is a serial modem.
2	Modem is a PowerBook Duo-style Express Modem.
3	Modem is a PowerBook 160/180-style Express Modem.

ASSEMBLY-LANGUAGE INFORMATION

The trap is _PowerMgrDispatch ($A09E). The selector value for GetIntModemInfo is 14 ($0E) in the low word of register D0. The bit field to set is passed in the high word of register D0.