Product Data Sheets (pdf)...2x1 and 4x1 DisplayPort Video Switches
Black Box Explains... Buffers
Product Data Sheets (pdf)...RS-232 Fallback Switch
A buffer (also called a spooler or a cache) is a temporary storage device used to share printers and compensate for a difference in speed and data flow between two... more/see it nowdevices. Buffers use RAM (Random-Access Memory) to take in data and hold it until the receiving device handles it.
A buffer serving a computer can be installed either internally or externally. Internal computer buffers are common in the forms of keyboard inputs, data caches, and video memory. An external buffer is usually used for printing.
An external buffer downloads jobs to the printer, freeing the computer so you can get back to work sooner.
A print buffers ports can be serial, parallel, or serial and parallel. Because a buffers ports operate independently of each other, a buffer also can be made to perform serial-to-parallel or parallel-to-serial conversion or to change the word structure and/or serial data rate (baud rate) of the data.
While most buffers are FIFO (First In, First Out), some advanced units can function as random-access buffers. For most serial buffers, hardware flow control is required, but some also support software (X-ON/X-OFF) control. Most buffers support printing of multiple copies of a document, provided the buffer has enough memory to store the entire print job. collapse
Black Box Explains... Basic Printer Switches
Mechanical—A mechanical switch is operated by a knob or by push buttons and uses a set of copper or gold-plated copper contacts to make a connection. The internal resistance created... more/see it nowby this type of connection will affect your signals transmission distance and must be taken into account when calculating cable lengths.
Electronic—Although electronic switches are controlled by knobs and pushbuttons like mechanical switches, the switching is accomplished with electronic gates not mechanical contacts. Electronic switches dont have the internal resistance of a mechanical switch—some even have the ability to drive signals for longer distances. And since they dont generate electronic spikes like mechanical switches, theyre safe for sensitive components such as HP® laser printers. Some electronic switches can be operated remotely. collapse
Black Box Explains... Printer Sharing with Windows
Unlike the earlier DOS operating systems, Windows® doesnt check to see if the printer is busy at the very beginning of the printing process. Windows will send out data to... more/see it nowstart a job even if the printer is signaling busy or unavailable. If your print sharer doesnt have a buffer, critical printer-initialization information can be lost before your job is started. Once the initialization information is lost, the printer cannot interpret the job correctly.
A buffered print-sharing device is the most practical solution. When Windows starts printing to a buffered port, it thinks its talking directly to the printer, and the critical initialization information is stored by the buffer. The buffer can send out a busy signal to Windows, so it delays sending more information until the buffer is accessible again. collapse
Black Box Explains... Single-Mode Fiber Optic Cable
Multimode fiber cable has multiple modes of propagation—that is, several wavelengths of light are normally used in the fiber core. In contrast, single-mode fiber cable has only one mode of... more/see it nowpropagation: a single wavelength of light in the fiber core. This means theres no interference or overlap between the different wavelengths of light to garble your data over long distances like there is with multimode cable.
What does this get you? Distanceup to 50 times more distance than multimode fiber cable. You can also get higher bandwidth. You can use a pair of single-mode fiber strands full-duplex for up to twice the throughput of multimode fiber cable. The actual speed and distance you get will vary with the devices used with the single-mode fiber. collapse
Black Box Explains...Advanced printer switches.
Product Data Sheets (pdf)...ServSwitch Summit
Matrix—A matrix switch is a switch with a keypad for selecting one of many input ports to connect to any one of many output ports.
Port-Contention—A port-contention switch is an... more/see it nowautomatic electronic switch that can be serial or parallel. It has multiple input ports but only one output port. The switch monitors all ports simultaneously. When a port receives data, it prints and all the other ports have to wait.
Scanning—A scanning switch is like a port-contention switch, but it scans ports one at a time to find one thats sending data.
Code-Operated—Code-operated switches receive a code (data string) from a PC or terminal to select a port.
Matrix Code-Operated—This matrix version of the code-operated switch can be an any-port to any-port switch. This means than any port on the switch can attach to any other port or any two or more ports can make a simultaneous link and transfer data. collapse