Routers, what’s in a name?

Posted on January 31, 2012 by SJE

Often the term router must be given some context. Depending on who you are talking to, the listener might think of a network router used on an Ethernet network, an A/V routing switcher or even a powerful tool for working with wood. I use all three, and am constantly amazed at the power and versatility of each in the hands of skilled personnel. Despite our focus on IP, this article will look at the A/V version.

For years, I have been a fan of the multilevel routing switcher, or as it is called in some circles, the crosspoint matrix. They are an essential part of nearly every broadcast and production facility’s infrastructure. Flexibility is the key advantage. Unfortunately, while the inputs and outputs increase linearly, the crosspoint count increases exponentially. This has kept some from purchasing these workhorses in favor of patch panels and other simpler solutions. With the coming of age of packet switching networks, it seemed that routers would become less useful. Nothing could be further from the truth.

I recently designed a control room for monitoring an IP-based (Microsoft Mediaroom) 700 channel headend that manages 10 separate markets from coast to coast as well as all of the supporting infrastructure. The system utilizes numerous technologies including composite A/V, ASI over coax and UTP, and multicast streaming of both MPEG-2 and MPEG-4 (h.264) over traditional TCP/IP networks. We have multiviewers and cyclers to constantly monitor all channels (national and local) on the STBs, and there are plenty of monitors scattered throughout the facility. In addition, numerous web servers provide status on alarming, as well as server and network health. In the end, the key to bringing the entire design together was a 64×64 HDMI/DVI crosspoint matrix.

Nearly 95% of the sources had either DVI or HDMI outputs. Monitors for computers as well as TVs typically support one or both and HDMI offers audio. All of the STBs from the various markets exist in our facility, now any STB from any market can be pulled up on our viewing wall or desks for QC checks. Our main viewing wall has computer outputs for the health displays, and because of the router, these too can be brought up on our desktops as needed. We ended up settling on two monitor types; one set of 42” displays for the viewing wall, and some low cost TVs for all desktop work. The TVs have HDMI and VGA inputs and are used for both the router outputs and our laptop/desktop PCs.

While none of the personnel had any experience with this type of router, all are pleased and wondering how we got along without it.

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Revisionist Thinking

Posted on December 14, 2011 by SJE

One of my early broadcast projects involved building a remote edit suite for a pair of Ampex VPR-80s. The suite was located in a corner of the studio about 50 feet from the machines themselves. Due to the cable route, the cables were close to 75 feet long. At the time, the only control other than the front panel was a parallel cable. As I recall, each connector was about 60 pins. These were solder pins that were placed in a large connector block (~2.5” x 1”). A pin inserter/extractor tool allowed the pins to be soldered outside the block then inserted. Inevitably, with that many pins, one or two were inserted into the wrong positions and the extractor tool made it relatively simple to correct. Relatively large gauge cable had to be used for several of the connections as the edit controller was powered by the machines. When it was all said and done, the remote cables weighed in at about 100lbs. Within a year, serial control became available. What a difference! Today, an Ethernet cable or even wireless is all that is needed to control a variety of equipment.

Technology has come a long way, and I am finding myself seeking features I would have never considered. For instance, the thought of a radio card inside a PC never made much sense when an inexpensive radio cost $50, but the PC was $1000 and the radio card another $25-$50. Recently though, I needed an audio amplifier with a web server. Why? I am building a control room for an IPTV headend and one unusually troublesome item is the number of remote controls on the desk. There are often two operators or more, and remotes are constantly being shuffled around. The new control room has provisions for audio at each operator desk as well as separate audio for the room. What I needed was a way to control the room audio without placing the amplifier in front of one operator and without a physical remote control. Several consumer manufacturers are offering iPad control, but in this application, an iPad is just another device to clutter the desk. Sure enough, Denon (and others) offer web-based remote control of their receivers. Problem solved.

It is interesting that the solution is essentially a PC inside of a radio, rather than the other way around. The question, and real point here is: how are you using technology? Are you applying old patterns such as parallel remote control to new technology? Or, are you thinking outside the box and seeking out new ways of doing things? Once new technologies are embraced, it often becomes harder to solve a problem using older methods; imagine trying to remote control a file server using a parallel cable.

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What are today’s broadcast skills?

Posted on October 24, 2011 by SJE

Lately there has been a lot of talk concerning broadcast skills. What skills are needed in today’s job market? A good place to start is with a thorough knowledge of audio (for those going into radio) and a similar knowledge of both audio and video for those wanting to succeed in television. Because this is broadcast, some RF knowledge is helpful. I say that because I know many studio engineers that never get near the transmitter. Obviously, RF knowledge (and electrical safety) is critical if you intend to work on transmitters. Beyond that, the things I always found important were excellent troubleshooting skills, general knowledge of many systems and the ability to work under pressure.

Times have changed. Technology continues to evolve. The basics (audio, video and RF) will always be important, but new skills involving computers, networking and workflows are also needed. Knowing what analog video looks like on a waveform monitor may be helpful, but is not critical in getting an ASI feed to the next device in the signal chain. Knowing how to calculate a subnet mask may be.

I have never had an interest in running the company’s business LAN. I get no thrill out of hooking up the office printer or endlessly patching or re-imaging the sales laptops, however, networked audio and video have distinct advantages. Replacing a facility full of coax and shielded twisted pair with Cat 5e or Cat 6 cabling allows an efficiency that was not possible in the days of analog equipment. Granted, the picture quality is not what was possible then either. Cameras tweaked to 700+ TVL might have made pretty pictures on CRTs, but maintenance was high, tubes cost real money and one wrong move by studio personnel could burn a highlight into a set of tubes in a heartbeat.

Compressed digital images are here to stay. Ever more sophisticated bit-rate reduction will not stop anytime soon. One of my co-workers is a master electrician, climbs towers and knows his way around any type of communication facility, be it satellite, telco or broadcast. Only a few years from retirement, he avoids servers simply because he is smart enough to know he does not know what he is doing. However, he can network numerous devices together, configure routers and switches as well as handle MPEG transport muxes without issue. As stated above, times have changed. Knowledge of fundamentals is important, but knowing and adapting to today’s technology is far more saleable in today’s world than clinging onto technologies that never worked as well as we remember.

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