3.2. Wildcard Characters

The use of the wildcard character, '*', can make programming the host controller much easier. Be careful when using wildcards, however, since they can generate a lot of traffic on the digital bus.

3.3. Using Acknowledgements

It is a good idea for the host program or control system to make sure that all connected Vortex devices have acknowledgment mode enabled (see the ACKMOD command). When acknowledgment

mode is on, a Vortex device will send an acknowledgment for each command it receives. Proper use of acknowledgments makes the host program more robust and makes supporting multiple hosts effortless. The rest of this section describes how to use acknowledgments to achieve these goals.

As a convenient example, let us imagine a host program with a graphical user interface (GUI). The user presses buttons on the GUI to enable or disable features of various linked Vortex devices. The buttons on the GUI reflect the current status of the corresponding feature.

When the user presses a button on the GUI to enable or disable a feature, the host program should send the corresponding command to the selected Vortex device. It may be tempting to update the status of the GUI button at this point, but this can cause problems if there are transmission errors or if there are multiple host controllers. The proper way to handle this is to only update the GUI controls based on acknowledgments received from the Vortex device.

To implement this, organize your code so that the functions that send commands are totally separate from the functions that receive responses from the Vortex devices. This also enables your host program to support the presence of multiple host controllers. For example, consider the following sequence of events.

1.Another host sends a command to a Vortex device.

2.The Vortex device responds with an acknowledgment that is broadcast to all of the other hosts.

3.Your host program receives the acknowledgment and updates the status of the corresponding control.

The result of this programming model is that all hosts and linked Vortex devices will always be synchronized.

For simple on/off features, your host program can make use of the toggle arguments to some commands (e.g., 'SSEN2'). By sending a toggle command when a button is pressed, and updating the button based on acknowledgments, your host program will not have to keep track of the status of the button.

In a similar fashion, many of the integer commands (such as gains) can be controlled by incrementing or decrementing them by a specific amount. For example, the command 'GAINIA>1 ' increments the input gain on channel A by 1 dB. The acknowledgment for this command will return the actual value that the gain was incremented to. Thus, to implement a volume control, your control program can send a command to increment the gain by 1 dB when the "up" button is pressed and decrement the gain by 1 dB when the "down" button is pressed. The control can update its level indicator based on the acknowledgment that is received.

Page 6 Page 8
Page 7
Image 7
Polycom RS-232 manual Wildcard Characters, Using Acknowledgements
Page 6 Page 8

RS-232 specifications

Polycom RS-232 is a key interface utilized in various communication and audiovisual systems, enabling effective integration between different devices. This technology employs a standard serial communication protocol that allows for robust control and communication, particularly in environments that require sophisticated audiovisual setups.

One of the main features of Polycom RS-232 is its ability to facilitate point-to-point communication over distances of up to 50 feet without the need for a repeater. This long-range connectivity is essential in large conference rooms and auditoriums where devices are often spread out over considerable distances. The serial connection is often more reliable than wireless options, which can be susceptible to interference.

Another notable characteristic is its versatile compatibility with a range of devices, including cameras, projectors, and interface panels. This allows users to control multiple devices from a single point, streamlining the operation of complex setups. The straightforward nature of RS-232 commands simplifies integration, which is a significant benefit for both installers and end-users.

Polycom RS-232 also supports various baud rates, giving users the flexibility to optimize communication speed based on their requirements. This adaptability ensures that users can achieve the desired performance, whether they are managing basic functions like power and volume control or more complex commands for switching video sources or adjusting settings.

The technology also features error-checking capabilities, which contribute to its reliability in communication. This reduces the likelihood of issues during operations, ensuring that commands are correctly received and executed. Additionally, its structured protocol aids in diagnosing and troubleshooting, making it easier to manage any issues that arise.

With its robust nature and proven reliability, Polycom RS-232 remains a pivotal technology in the realm of audiovisual communications. Its combination of long-range capabilities, compatibility, flexibility, and reliability makes it an essential tool for enhancing the efficiency of modern communication environments. As technology continues to evolve, the importance of dependable interfaces like Polycom RS-232 cannot be overstated, ensuring seamless integration and operation of sophisticated communication systems. Whether used in educational institutions, corporate environments, or event venues, Polycom RS-232 guarantees a streamlined experience in device management and control.
Top Page Image Contents