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Future-Proof Your Network

Future-Proof Your Network

Category cables have been in use for a number of years. Most consumers will know these as network cables, Ethernet cables, or possibly even Cat-5 cables. However, they may not understand what Cat-5 means or how to determine if that is really the cable in use. Category cables have been upgraded multiple times and the vast majority of consumers are probably using Category 5e cable in their home networks. As our networking needs have increased, so have the cables, and a change is already underway to go beyond Cat-5e.

Category cables are designed to transfer data within networks. They are the standard method of connectivity for Ethernet networking. Cat-5e is still the most common cable but it is close to its limits. In fact, larger networks requiring higher bandwidth and better interference protection have already abandoned 5e. We are demanding more from our networks, transferring more data at faster speeds than ever before. In addition to Ethernet networking, category cables can now be used for audio and video networks. Dante audio networks transfer uncompressed multi-channel audio via category cables and HDBase-T promises to be the future of home audio and video integration. HDBase-T transmits high-definition audio and video, Ethernet, device control signals, USB data, and power all through one category cable. Category 5 cables cannot handle this much data.

In order to meet the bandwidth needs of newer networks, we must use Category 6 cable. Category 6 improves bandwidth and crosstalk protection over previous generations of category cable. It has been tested to perform up to 250 MHz and can transmit 10 Gigabits per second (Gbps) for up to 55 meters. This is not to say it cannot go beyond these points, only that this is how the cable was tested. Category 6 cables also have several shielding options. You can purchase cables in the more traditional Unshielded Twisted Pair (UTP) construction, or with shielding around each twisted pair, the full cable assembly, or both. Hosa’s CAT-600BK series is an example of Category 6 cable with both shielding around each twisted pair and around the entire assembly.

In addition to the original Category 6 cable, a revision to the standard later added Cat-6A cable, also known as Category 6 Augmented. This cable provides even better protection against crosstalk and has been tested up to 500 MHz. Cat-6A can run 10 Gbps Ethernet up to 100 meters.

It’s important to note that while Cat-5e was the updated version of the original Category 5 standard, there is no Cat-6e version recognized by ANSI/TIA.

The good thing about category cables is that they are backward compatible. If you are setting up a new network, it is a good idea to use Cat-6 cable even if you do not believe your network will need the added bandwidth. Taking that step now should make things easier in the future.

- Jose

A Balancing Act

Questions about balanced and unbalanced audio come up frequently and it is an important concept to understand when hooking up pro audio equipment. Before you start plugging things in, check if your devices use balanced or unbalanced audio so that you may purchase the correct cables only once.

Analog audio cables consist of a shield and one or more conductors. Corresponding connectors must then have at least two points of contact. Cables that only have a contact point for the shield and one signal are unbalanced. An example of this would be a guitar cable, as it uses 1/4” TS connectors. In this example the sleeve of the connectors is the shield and the tip is used for the signal. The problem with unbalanced cables is that if any noise enters the signal as it passes from one end to the other, that noise is added to the sound when it reaches its destination. This is precisely the reason balanced audio was created.

In balanced audio the signal is duplicated and carried on two separate conductors. The trick is that one of the signals is flipped, or inverted, to be the polar opposite of the other; one is positive and the other negative. At their destination, the negative signal is changed back to positive and combined with the original. At the same time, the noise traveling on the negative signal is also flipped and becomes the polar opposite of the noise on the positive signal. The result is any noise equally picked up by both conductors is rejected at the destination. Microphone cables, like the Hosa Edge CMK-010AU, are examples of balanced cables. Microphone levels are very low and the best way to keep them noise-free is to use balanced audio. Microphone cables with 3-pin XLR connectors, audio interconnects with 1/4” TRS connectors, and even interconnects with 3.5mm TRS connectors are examples of balanced audio cables if they are interconnecting devices using balanced audio.

It seems pretty easy when it comes to cables, right? If the cable has two points of contact, it’s unbalanced; and if it has three, it’s balanced. Well, not quite. A 2-conductor cable is not strictly a balanced cable. It’s the devices in use that determine the function of the cable. The Hosa CSS-110 is a 1/4” TRS interconnect. If you use this cable to go from the balanced left output of a mixer to the balanced input of a powered monitor, it is a balanced audio cable. Take the same cable and use it to hook up the stereo headphone output of a mixer to a headphone amp, and you’ve got an unbalanced stereo cable. In the second example, one conductor is carrying the left output of the mixer and the other, the right output. This cable is not carrying the same signal along both conductors and is therefore, not passing a balanced audio signal.

It’s important to always verify the type of cable you will need for the equipment you plan on connecting. Take the time to understand the connector types and the signal transfer formats before you begin researching the cable you wish to buy. Knowing this information before you go shopping for cables will save you time, which is better spent putting your new pro audio equipment to use.

- Jose

The DB-25 Enigma

Many times, people look at the jacks on the back of a device to figure out what cables they will need. While this is not really the best way to figure things out, most of the time it will get results. If you see an RCA jack and ask for an “RCA cable”, you’ll probably find a suitable cable (though there are different types of cables that use the RCA connector). But if you don’t get a little more information, you’ll most likely run into trouble when you see a DB-25 jack on the back of your audio device.

DB-25, or D-sub, connectors were originally created for computer applications. The audio industry adopted the DB-25 as a way of getting multiple channels in and out of devices while taking up minimal space. In this regard, the DB-25 connector works great. However, the use of this connector is problematic because there is not one universally accepted way of wiring it. In fact, there are three widely used wiring conventions when it comes to DB-25 in the audio world.

Some devices use D-sub connectors as a way of inputting or outputting eight channels of balanced analog audio. Each balanced channel requires three pins—one for the positive signal, one for the negative, and one for the shield—and each channel is grouped in a triangle pattern by taking two pins from one row and one pin from the other. Eight channels require 24 pins and pin 13 is simply not used. The Hosa DTM-800 series balanced snake is wired this way. It connects to the DB-25 output and breaks out to eight XLR male connectors. The Precision 8 mic preamp by True Systems uses a DB-25 connector to output all eight channels. This makes it possible to run a single cable with eight channels to an audio interface or mixer.

Professional audio devices can also use one DB-25 connector for eight channels In & Out (I/O) using the AES3, or AES/EBU, format. This digital audio format enables devices to send two channels of audio along one balanced audio line. This is where it really gets fun, as there are two standards for AES/EBU multi-channel I/O—and manufacturers choose which one to use.

The first is known as the Tascam wiring standard. The Tascam wiring standard is the same as the analog standard at the DB-25 connector end. The wire, however, must be different, as it is not passing analog sound. The AES3 specification requires 110-ohm balanced cabling for AES/EBU signals. Unlike analog snakes, AES/EBU snakes carry two digital channels on each balanced line. This means through one DB-25 snake, the device can send eight channels and receive eight channels simultaneously. If you are using a digital snake that breaks out to XLR connectors, it will have four male and four female XLR connectors instead of four like connectors on the analog snakes. Avid and Universal Audio are two companies using the Tascam standard. Avid’s ProTools HD I/O uses AES/EBU via a DB-25 jack.

Companies such as Apogee and Mackie, among others, have adopted the Yamaha wiring standard for their AES/EBU I/O. The wire is the same as that used for the Tascam digital snakes but the pin configuration is much different. In this case, the ground wires are on one side of the connector, while the other side gets the conductors. The Lynx Aurora 16 AD/DA converter uses AES/EBU with the Yamaha standard.

Note that if you are connecting two digital devices, you must make sure to use the correct pinout for each. If one of your devices uses the Tascam standard for its AES/EBU I/O and the other uses the Yamaha standard, you can still use them together. You must, however, use a snake with the Tascam pinout on one end and the Yamaha pinout on the other. Analog to digital is not as simple. You cannot use a DB25 snake to interconnect AES/EBU and analog signals. This would require a separate interface, which is a topic for another discussion.

The next time you turn to the back of your device for cable answers, remember the connector type is not everything—especially with DB-25. Your first question should be whether you’re looking at an analog or digital connection. If it’s digital, the next step is to figure out the wiring standard the device uses. Taking these steps will decrease headaches down the road and ensure you purchase the right DB-25 snake the first time.

- Jose

Y or Y Not?

The Y cable earned its name from the way it looks. There is a single connector on one end with a cable that splits, either as a zip cable or with a small box that conceals the split, and finishes with two connectors at the other end. A stereo breakout meets this same visual description and yet does not perform the same way as the typical Y cable. Let’s take a look at the difference between the two.

A Y cable is used when there is one signal that must go to two different places. For example, when you have one 1/4-inch TRS headphone output and you want two people to listen to the same thing on their own headphones with 3.5 mm connectors. The quickest solution to this problem would be a Y cable with a single 1/4-inch TRS male to dual 3.5 mm TRS female jacks. Each of the two headphones will get exactly the same signal. The cable is wired so each contact on the single end connects to the equivalent contact of each connector on the dual end. Be advised that a traditional Y cable is designed specifically to split a signal. Using a Y cable to combine two signals is not recommended because you have no control over the way the signal is combined.

A stereo breakout, on the other hand, is designed to do what the name states, it breaks out a stereo signal into two discrete points. A common situation requiring a stereo breakout is playing music from an iPod® through an audio mixer with 1/4-inch TS inputs. The solution is a 3.5 mm TRS to dual 1/4-inch TS stereo breakout cable. You connect the 3.5 mm end to the iPod and on the other end you’ll have the left signal (tip of the connector) on one of the 1/4-inch connectors and the right signal (ring of the connector) on the other, allowing you to connect each to its own input on the mixer. When used properly, a stereo breakout can be used in either direction. You could use the same breakout from the previous example to take the left and right outputs of a mixer and connect them to a laptop equipped with a 3.5 mm stereo input.

It’s important to know what you need to accomplish in order to select the right cable. Hopefully this has shed some light on these two popular audio problem solvers so that you can always make the right choice.

- Jose