About Telephone Terminals (IM: Telephony)

Inside Macintosh: Telephony /: Chapter 2 - Telephone Terminals

About Telephone Terminals
A telephone terminal (or, more briefly, a terminal) is any hardware device that provides a physical interface between a Macintosh computer and a telephone network. A telephone terminal might also provide a physical interface between the telephone network and a telephone set attached to the Macintosh computer. A telephone set is any hardware device that can be used to manually dial, answer, or otherwise manipulate telephone calls. Alternatively, a telephone terminal that has speakerphone capability is able to use the microphone and speakers of the Macintosh computer to which it is attached as the voice input and output devices.
A telephone terminal is directly controlled by a device driver. In turn, the device driver communicates directly with a telephone tool. As you saw in the chapter "Introduction to Telephony on the Macintosh," you need to find and configure a telephone tool before you can open a telephone terminal. All communication between your application and the terminal is handled by the associated telephone tool.

Note
A single telephone tool can be associated with more than one telephone terminal. For instance, the Apple ISDN telephone tool can support two or more ISDN cards in a computer. Some telephone tools, however, cannot be associated with more than one telephone terminal. The GeoPort telephone tool can currently support only one GeoPort pod.
The Telephone Manager lets your application monitor and control the physical components associated with a terminal. Telephone terminals might support some or all of these components:

a handset or other physical device that contains a microphone and speaker. The handset might be part of a speakerphone, a telephone set that contains a microphone and speaker (thus allowing hands-free use). The handset and speakerphone each have a hook state that indicates whether the device is on hook or off hook. The hook state is changed by the hookswitch. For a handset, the hookswitch is the device that is depressed when the handset is hung up. For a speakerphone, the hookswitch is usually a button on the telephone set.
a ringer or other device that can alert the user of activity on the telephone terminal.
a keypad that contains the standard 12 buttons ('1' through '9', '0', '*', and '#').
a display that shows alphanumeric data (for example, a telephone number or date and time information).
a videodisplay (that is, a device that can display video images). A telephone set that contains a videodisplay is a videophone.

In addition, a telephone terminal might have other features, such as the ability to dial a telephone number while the handset is on hook. See page 2-8 for a complete description of all telephone terminal features supported by the Telephone Manager.