WSRL VOIP Page-1

WSRL.ORG / Voice Over IP - Feb, 2010 - Revised Feb, 2010 - Page 1

The motivation for this page came from two directions. A lifetime ago I was part of a support team involved in the installation and operation of large Nortel SL-100 voice switching systems. These systems had amazing capabilities for the day. Now, being retired, I live in rural Western Colorado and the local telephone company is about as

Intel BoxD945GCLF Integrated

miserable as telephone companies get. A VOIP PBX provides the opportunity to recapture virtually all of the features of the SL-100 product and more. This page is the start of a project to build a small, power efficient PBX system based on an Intel Atom integrated motherboard. As I learn and VOIP capabilities develop, they will be documented here. This is a fairly large topic area. The software for a small SOHO based VOIP PBX system can be obtained for no cost. Recent reductions in the cost and the availability of hardware for a small VOIP PBX project has made this effort too good to pass up. Because the software is largely based on Linux, software topics here will be related to topics on my Linux page.

I must also say this area, in my experience, is dominated by commercial types with dollars in their eyes. Information can be hard to come by. Equipment manufacturers cater to service providers and large PBX installers. The Windows® operating system is also an ever present and unfortunate scourge to this field. I'm afraid, by choice, will will provide NO information on anything Microsoft related. In general, the small VOIP user, I've found, is largely left out in the cold. This site, in a small way, hopefully will help with this great technology.

What Is It? -

In simplest terms, VOIP is analog voice converted to digital data which is then processed and transported over the Internet. Rather than set up dedicated point-to-point continuous circuits as was/is done with legacy telephone systems, this technology transports packets of digital voice data. If analog voice energy is not available/present at a telephone handset, nothing is transported. This, in part, provides large efficiency/cost gains common to this technology verses older telephone systems. The picture to the right represents a small but full blown VOIP PBX system capable of supporting soft phones, regular phones and software controlled electronic multi line phones. There are no plans to interface wire land line telephone circuits to this system. All trunking will be provided via the Internet. This is a rural area. The support of wire telephone facilities is becoming harder and more costly as time proceeds. A 6 Mbps Internet circuit is delivered here via Motorola Canopy radio.

PBX Power Draw - Watts

Intel 945 CPU -

The links to the right provide access to the technical manual and product guide for this product. The MTBF for the board is quoted on page 54 of the technical manual as 79,088 hours or about 9 years. As stated on page 61 of the same manual, the board will boot and run without monitor, keyboard or mouse attached. With those three devices still attached, the power consumption for the board was measured at 38 watts. At 10 cents per KWH, the board will cost about 9+ cents per day or $2.75 per month to run. In my case, this compares to a phone bill of $29.20 per month. This leaves plenty of money left to purchase additional monthly services. Needless to say, the board is fully compatible with the CentOS Linux distribution. Just for the record, the PC used to setup and control the Atom MB is an Intel i7 Quad Core (DP55KG) w/Nvidia 9800GTX video. The machine runs (K)ubuntu Karmic Koala perfectly and no, I wouldn't be caught dead running Windows® anything.

Audience and Intended Objectives -

The audience for this project could include farm or rural families with multiple residences in close proximity. Small or home offices of all types could also benefit from such a system as would anyone needing to transfer calls over a large area. For small installations, it's important to keep the overall power consumption as small as possible. As stated above, the 38 watt load seems reasonable to me for a small system. I have no doubt that future electronics will be even more efficient. It's important to realize that this type of system can support trunking, at reasonable cost, to locations hundreds if not thousands of miles distant. Using the Internet, extensions off this system can be located like distances from the PBX.

House/structure wiring is another issue. These system can be implemented using wireless technology but I feel you will find it much more convenient to use this technology over a standard wired Ethernet system. Hopefully, there is no one out there wiring houses using old style telephone wire. CAT5e is easily obtained at Home Depot as well as other sources. It doesn't take a lot of effort to completely

Network Topology

wire a new home with CAT5e, running each cable back to a central point in the home. For reference, I have repeatedly run 100 Mbit over 50-70 feet of good quality CAT3 cable without problems. I would be quite surprised if 1000 Mbit could not be transported over quality CAT5e for distances in the range of 70 feet.

Network Topology -

The picture to the right depicts what you want to functionally end up with. In a real network there will, of course, be more switches, phones & PCs in addition to a router. For the PBX, a keyboard, monitor and optical drive are required to load the software but once loaded, it's desirable to view and control things from another PC. The PBX keyboard, monitor, mouse & optical drive are not needed.

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