Technical Note about the Audio Inputs

Model AC1120A, AC1121A, AC1122A, AC1123A

The audio input on the basic unit uses standard 3.5mm mini-stereo connectors. To use these with PC audio, standard male-to-male audio extension cables would be required. To connect from typical TV sources with separate right and left connectors, 3.5mm male to 2 RCA cables would be needed.

Since the audio inputs are unbalanced (single ended), the ground reference of the source has to be the same as the matrix. Of course the cable connecting the two is tying the grounds across but if there are currents flowing in the ground it can create potential differences that would manifest as noise. The quality of grounding at the audio source and the matrix are important. For example if the input source is a desktop PC, as long as the PC is properly grounded and the audio cable length is not excessive, you can expect good results. On the other hand if the input is a notebook PC running on battery, there is no ground reference at the source so it gets its reference through the audio (and video) cable connection to the matrix. This should also be okay. However if it is plugged in through its external power brick, noise can be induced. This is because most notebook power supplies do not properly provide an AC ground path to the system ground (some only have only 2 prong AC cords). The switching power supply circuit will inject noise into the audio lines. In this case the solution may be to attach a low resistance ground strap to the notebook. The other option for eliminating the noise is to use a stereo audio Balun (or isolator). The Balun essentially couples the audio through a transformer so the audio grounds are isolated. Baluns can also cure noise pickup in long cable runs.

2.2 Output Audio & Video Connections

Figure 3 – Standard matrix audio and video outputs

The video output connectors are HD15 female. These are compatible with PC’s VGA video signal (RGBHV). The Matrix is also compatible with YPbPr HDTV signals with the use of HD15 to 3 RCA adapter cables.

1121A, 1122A, 16x16 and 8x8 VGA/HDTV Video Matrix Switch with Front Panel, RS232, and Optional Audio & IP Control, AC1120A, 1123A specifications

The Black Box 1123A, AC1120A, 16x16 and 8x8 VGA/HDTV video matrix switches represent a versatile and powerful solution for any audio-visual application. With their capability to switch signals from multiple sources to multiple displays, these matrix switches are ideal for conference rooms, control rooms, and education environments. Each model features a user-friendly front panel for immediate access and control, allowing operators to easily manage video routing without needing advanced technical skills.

The 1123A and AC1120A models support 16x16 and 8x8 configurations, respectively, providing flexible connectivity options for various setups. These matrix switches can accommodate a range of video standards, including VGA and HDTV, ensuring compatibility with a wide selection of devices and displays. This flexibility is essential in environments where different types of video sources and outputs are commonly used.

One of the standout features of the Black Box 1123A and AC1120A is the RS232 control option, which allows for remote management and automation through a serial connection. This capability is particularly beneficial in complex installation setups, enabling users to integrate the matrix switch into existing control systems easily.

Moreover, these models come equipped with optional audio control functionalities, allowing for the simultaneous management of audio and video signals. This integration is critical for environments where synchronized audio-visual output is necessary, such as in presentations or live event settings.

The matrix switches are designed with high-quality components that ensure minimal signal degradation and excellent video quality, even at extended cable lengths. Additionally, they support a range of resolutions, making them versatile enough to cater to both standard and high-definition video signals.

The models 1122A and 1121A complement the 1123A and AC1120A with additional features and enhanced capabilities, ensuring a comprehensive product range to meet diverse client needs. With a reputation for reliability and performance, Black Box continues to lead the market in video matrix switching technology.

In summary, the Black Box 1123A, AC1120A, and their counterparts offer an advanced solution for modern audio-visual installations. Their robust features, compatibility, and user-friendly control options make them an exceptional choice for any organization seeking to enhance their video management capabilities.