[This is preliminary documentation and subject to change.]
One of the features of Microsoft WebTV for Windows is the ability to schedule the recording of future shows that a user selects from the Program Guide. If a user has set a reminder within Microsoft® WebTV® for Windows® to automatically record a show, WebTV for Windows sets a task in Task Scheduler that at a specific time starts helper applications. At the specified time, these helper applications can start and then run a VCR or similar device to record a selected show. You must create one or more helper applications to tune a VCR and start and stop recording a show and set values for those applications in the registry. Although you can create separate applications that start and stop recording a show, it is possible to write one application to do both. In addition, the reminder for recording in WebTV for Windows also requires a specific helper application to wake up your other helper applications. Unless you intend to create and set in the registry your own wake-up application, the record reminder uses the Tvwakeup.exe application, a component of Broadcast Architecture, as the default. The Tvwakeup.exe application starts your other helper applications with a specific command-line syntax. To use Tvwakeup.exe, you must enable your helper applications to process the specific arguments of this syntax.
Although some VCRs might have the ability to be controlled by a computer from an RS-232 connection, most VCRs must be controlled by a remote control connected to a computer's serial port.
The following topics describe in order the basic implementation tasks involved in creating a command-line application that Broadcast Architecture uses to automatically record shows:
The software supporting Broadcast Architecture includes the sample application Ir.exe, a command-line application that controls a VCR through an infrared remote control. To locate Ir.exe, see Broadcast Architecture Sample Applications.
To locate more information about setting a reminder for recording shows and the command-line syntax that Tvwakeup.exe starts applications with, see Setting a Record Reminder. To locate more information about the registry entries in which to store the path and file name of your helper applications, see Registry Entries for WebTV for Windows.