The interaction of telephony and video signaling places special demands on VDSL2 splitters. When a telephone is “off-hook,” the battery at the central office provides -48VDC over the phone line. When the phone is ringing, peak ring voltage is 127 volts. If the subscriber answers the phone (a condition called “ring trip”) at the negative peak of the voltage cycle, the instantaneous voltage (a combined -48VDC from the CO battery and -127 from the ringer) adds up to -175 volts. When this happens, an ordinary splitter can allow high-voltage, high-frequency transients to enter and interfere with the VDSL2 spectrum. This, in turn, can cause corruption or loss of data packets and interference with video signals.

The problem is not too significant in the case of data since TCP/IP can request packet retransmission. Video, on the other hand, is a streaming service and does not allow for retransmission. In order to provide uninterrupted video service and compete with video services on cable, the service provider must use high quality video-grade VDSL2 splitters. These splitters work with the DSL chipset to reduce or eliminate problematic ring trip effects. Appropriate splitters must be configured at the CO and in the network interface device at the customer premise.

See more VDSL2 considerations in our free whitepaper.

Need a few training credit for home networking? Then check out suttle’s online training program. This training program covers home networking basics in an easy to follow format and is available for you to take it whenever you need it: 24 hours a day, 7 days a week. Just login to our website with your same user name and password (or create one from our login page) to login to the Suttle Training section of our website located under the support menu. Once logged on work your way through each chapter passing the test at the end of each to not only recieve BICSI and CEDIA credit ¹ but to become Suttle Certified to offer our 25 Year Warranty ² on certified systems. It’s that easy.

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¹ See documentation requirements outlined on your “my training” page in the training area as well as the requirements on the certification association’s website.
² Rules and restrictions apply.

Suttle’s new video area features a new HomePNA™ Technology Overview video, a brief explanation of what HomePNA™ is along with its features and benefits, as well as Suttle HomePNA™ product demo videos for both the Gigabit Ethernet Adapter and the Master and Endpoint Adapters (coming soon). Stay tuned for future product information and demo videos in the coming weeks and months ahead in Suttle’s new video area www.suttleonline.com/video.

For VDSL2, as the cable length from the DSLAM (Digital Subscriber Line Access Multiplexer) to the customer premise increases, signal strength decreases and the line becomes more susceptible to noise. Additionally, every component or extension that is attached to the cable between the DSLAM and the customers will also introduce impedances that will either reduce the signal strength further increasing the insertion loss, add signal reflections decreasing the return loss, or degrade the balance of the twisted pair cable increasing the noise.

Due to the frequency sensitivity of the HomePNA signal there are a few things that should be considered when training technicians installing HomePNA over coax.

• Compression connectors are a must. Crimp connectors can damage the dielectric and have an uncontrolled connection to the shielding.
  (Side Note: Suttle TWiN Lock™ and SURE Lock™ connectors are 360° compression connectors that maintain complete contact with the cabling.)
• Make sure the dielectric of the coax is flush with the inner base of the compression connector (not protruding or recessed in relation with the inner base). This helps guarantee a solid connection.
• Use resistive splitters instead of standard type splitters whenever possible. With standard coax splitters, the port isolation is too high. If your only option on an install is to use a standard splitter the input must be left open (unconnected).
• Test, Test, Test – Insufficient testing is one of the leading causes of reported problems and often leads to excessive modification to home wiring, which is time consuming. Changing a connectors only takes a minute, but changing a cable can take an hour. A lack of testing leads to uncertainty and over time, creates a preference for un-necessary re-wiring.

For more information visit www.homepna.org .