Black Box Explains...How a line driver operates.
Driving data? Better check the transmission.
Line drivers can operate in any of four transmission modes: 4-wire full-duplex, 2-wire full-duplex, 4-wire half-duplex, and 2-wire half-duplex. In fact, most models support more... more/see it nowthan one type of operation.
So how do you know which line driver to use in your application?
The deal with duplexing.
First you must decide if you need half- or full-duplex transmission.
In half-duplex transmission, voice or data signals are transmitted in only one direction at a time, In full-duplex operation, voice or data signals are transmitted in both directions at the same time. In both scenarios, the communications path support the full data rate.
The entire bandwidth is available for your transmission in half-duplex mode. In full-duplex mode, however, the bandwidth must be split in two because data travels in both directions simultaneously.
Two wires or not two wires? That is the question.
The second consideration you have is the type of twisted-pair cable you need to complete your data transmissions. Generally you need twisted-pair cable with either two or four wires. Often the type of cabling that’s already installed in a building dictates what kind of a line driver you use. For example, if two twisted pairs of UTP cabling are available, you can use a line driver that operates in 4-wire applications, such as the Short-Haul Modem-B Async or the Line Driver-Dual Handshake models. Otherwise, you might choose a line driver that works for 2-wire applications, such as the Short-Haul Modem-B 2W or the Async 2-Wire Short-Haul Modem.
If you have the capabilities to support both 2- and 4-wire operation in half- or full-duplex mode, we even offer line drivers that support all four types of operation.
As always, if you’re still unsure which operational mode will work for your particular applications, consult our Technical Support experts and they’ll help you make your decision. collapse
Black Box Explains...Advantages of fiber optic line drivers.
Fiber optic line drivers are much better for communications than copper-wire alternatives because they offer three main advantages: superior conductivity, freedom from interference, and security.
Superior conductivity for increased performance
The glass... more/see it nowcore of a fiber optic cable is an excellent signal conductor. With proper splices and terminations, fiber cable yields very low signal loss and can easily support data rates of 100 Mbps or more.
Immunity to electrical interference
Because fiber optic line drivers use a nonmetallic conductor, they dont pick up or emit electromagnetic or radio-frequency interference (EMI/RFI). Crosstalk (interference from an adjacent communication channel) is also eliminated, which increases transmission quality.
Signals transmitted via fiber optic line drivers arent susceptible to any form of external frequency-related interference. That makes fiber connections completely immune to damaging power surges, signal distortions from nearby lightning strikes, and high-voltage interference. Because fiber cable doesnt conduct electricity, it cant create electrical problems in your equipment.
Electronic eavesdropping requires the ability to intercept and monitor the electromagnetic frequencies of signals traveling over a copper data wire. Fiber optic line drivers use a light-based transmission medium, so theyre completely immune to electronic bugging. collapse
Black Box Explains... Industrial modem benefits.
Not all modems shuttle data in air-conditioned, climate-controlled comfort. And modems that operate in cozy environments have absolutely no business being exposed to harsh industrial conditions or to the elements.
But... more/see it nowjust because you work in a rough-and-tumble place doesnt mean you have to sacrifice the convenience of a good modem. Instead, you should opt for an industrial modem. There are many industrial modems built for various degrees of extremity.
Survivability depends on reliability.
Sure, standard modems give you access to data in remote sites or enable you to service equipment on the plant floor—and you can do all this from the convenience of your office. However, these benefits are only possible if your modem can continue to function in its environment. And since standard modems arent built for adverse conditions, theyre not going to be reliable.
No penalties for interference.
Electrical control equipment—such as motors, relays, compressors, and generators—emit electromagnetic interference (EMI) that can affect the performance and reliability of a standard telephone modem.
EMI is emitted through power lines, the RS-232 communications cable, or through the telephone line itself. The very means of data communication, cable, is often the worst enemy of the standard modems that use it.
An industrial modem, on the other hand, has filters and superior EMI immunity to protect itself and your data. If you build your electrical cabinets to UL® or CSA standards, remember that your modem must also conform to UL® standard 508.
They go to extremes.
Temperature is the biggest killer of electronic equipment in industrial environments. The heat generated by industrial equipment in sealed enclosures or where space is a premium can make the temperature as much as 50 °F higher than the surrounding environment.
So standard modems cant take the heat. But what about being outdoors in the other extreme, cold weather? Well, standard modems cant take the cold either.
If you install your equipment in remote outdoor locations, it must work on the coldest days— especially those cold days when you least want to get in the car and go to the site to repair a standard modem that froze up.
Whether theyre placed in manufacturing environments or the great outdoors, industrial modems get the data through when you need it. They go to extremes for you.
Heavy metal for all kinds of banging around.
Industrial modems are built with durable metal enclosures that protect circuitry in rough conditions and ward off signal-disrupting EMI. Plus, they feature steel-bolt flanges to anchor them. In short, industrial modems can take the physical, heavy-duty punishment thrown their way.
So where exactly can you use an industrial modem?
• Heavy industry and manufacturing
• Oil and gas fields
• Storage sites
• Utility substations
• Agricultural projects
• Military facilities
• Research installations
• Water/wastewater systems
and another thing!
If dedicated copper lines cant be run through industrial environments, or if the fiber optic option is cost-prohibitive, there are also wireless industrial modems that make line-of-sight connections. If theres a way to get the data through, industrial modems will get the job done.
Industrial modems remain in service for a very long time. But if you ever need a replacement that is hardware or software compatible, be assured that Black Box continues to support its products year after year—so you don’t spend your time re-engineering systems if you have to make a replacement. collapse
Black Box Explains...RS-232.
RS-232, also known as RS-232C and TIA/EIA-232-E, is a group of electrical, functional, and mechanical specifications for serial interfaces between computers, terminals, and peripherals. The RS-232 standard was developed by... more/see it nowthe Electrical Industries Association (EIA), and defines requirements for connecting data communications equipment (DCE)—modems, converters, etc.—and data terminal equipment (DTE)—computers, controllers, etc.) devices. RS-232 transmits data at speeds up to 115 Kbps and over distances up to 50 feet (15.2 m).
The standard, which is functionally equivalent to ITU V.24/V.28, specifies the workings of the interface, circuitry, and connector pinning. Both sync and async binary data transmission fall under RS-232. Although RS-232 is sometimes still used to transmit data from PCs to peripheral devices, the most common uses today are for network console ports and for industrial devices.
Even though RS-232 is a “standard,” you can’t necessarily expect seamless communication between two RS-232 devices. Why? Because different devices have different circuitry or pinning, and different wires may be designated to perform different functions.
The typical RS-232 connector is DB25, but some PCs and other data communication devices have DB9 connectors and many newer devices have RJ-45 RS-232 ports. To connect 9-pin PC ports or RJ-45 to devices with 25-pin connectors, you will require a simple adapter cable. collapse
Black Box Explains...DIN rail usage.
DIN rail is an industry-standard metal rail, usually installed inside an electrical enclosure, which serves as a mount for small electrical devices specially designed for use with DIN rails. These... more/see it nowdevices snap right onto the rails, sometimes requiring a set screw, and are then wired together.
Many different devices are available for mounting on DIN rails: terminal blocks, interface converters, media converter switches, repeaters, surge protectors, PLCs, fuses, or power supplies, just to name a few.
DIN rails are a space-saving way to accommodate components. And because DIN rail devices are so easy to install, replace, maintain, and inspect, this is an exceptionally convenient system that has become very popular in recent years.
A standard DIN rail is 35 mm wide with raised-lip edges, its dimensions outlined by the Deutsche Institut für Normung, a German standardization body. Rails are generally available in aluminum or steel and may be cut for installation. Depending on the requirements of the mounted components, the rail may need to be grounded. collapse
Black Box Explains... Spread Spectrum wireless technology.
Frequency-Hopping Spread Spectrum wireless communication provides error-free transmission, top security, and high levels of throughput without the need for an FCC site license. The key to Spread Spectrum is a... more/see it nowfrequency-hopping transceiver.
Narrow-band frequency hoppers use a predefined algorithm to maintain synchronization and high throughput between master and remote modems. They achieve this by continually switching or “hopping” from one transmission frequency to another throughout the Spread Spectrum band. The sequence of frequencies is very difficult to predict and thus nearly impossible to eavesdrop on or jam. If interference is encountered at any particular frequency, the built-in error correction detects it and resends the data packet at the next frequency hop. Because EMI/RFI interference rarely affects the entire available bandwidth, and each frequency hop is at least 6 MHz, the radio transmitter has access to as many as 100 frequencies within the spectrum to avoid interference and ensure that data gets through. collapse