Symphony / Computer Preparations

First, obtain one Proxim Symphony PnP ISA cordless networking card for each node in your network. Check out www.shopper.com or your local Office Max for the best prices.

Included in the box will be:

You should initially setup your Symphony card using a Windows machine.  The setup should go through smootly and is covered completely in the user's manual.  Next, check the device manager and record the card's assigned IRQ and IO port range.  Example: IRQ 15 and port 0x208.

Refer to the Symphony Installation & Setup section for more detailed information.

Your Symphony card will most likey come with a SMB style connector for its RF output jack, unlike the threaded jack shown on the Symphony's box.  This connector is the most useless thing in the world.  What you want to do is replace it with a higher quality RF connector that will allow you to hook it up to an external antenna.  This is were the cellular phone comes in.  Most cellular phones have TNC connectors for their RF output jack.  These connectors also have about eight centimeters of factory installed, small coaxial cable.  What you want to do is remove this (we'll call it the TNC pigtail) from the cellular phone and solder it in place of the SMB jack on the Symphony.  This will require patience and proper soldering equipment, so make someone else do it.   :)

Tips from Brian Oblivion:  Those RF connectors are a *bitch* to get off the proxim cards.  Damn thing acts as a heatsink.  Trick is to suck the solder out of the middle RF conductor, then apply heat to two of the ground legs at a time (with a wide soldering tip.) and "rock" it out gently out of it's holes, by alternating between the two pairs of legs, all with the card in a vise.  Clean up with some #3 solder wick.

If you can't find a cellular phone with the proper adapter, use the Ericsson cellular phone adapter from Radio Shack.  The steps are the same, just cut off the end of the adapter that would go into your cell phone and solder the coax in place of the SMB jack.

Here is a pictoral overview of the TNC pigtail installation.

In order to maintain low loss in the external coaxial cable you'll be adding, you may want to build a small, dedicated Linux router that you can place near the actual antenna installation.  This might be difficult for outdoor installations, but will be worth it.  All you need for the router is a computer that will have a Symphony card, 10baseT Ethernet card, and a floppy drive.  See the Linux router project for more information.

You'll have to use 10baseT Ethernet, or any other balanced signal system, to avoid any ground loops that may occur by having hardware located in seperate buildings.  Be sure to also install surge protection on all your Ethernet cards and incoming power lines.

You may have to do some fancy weatherproofing if the router will be kept in a harsh enviroment.  Install temperature monitoring hardware/software, a fan/heater, and a UPS which you can all control remotely.  Refer to this Slashdot thread on some tips for outdoor computer cases.

If a dedicated routing computer is not possible, any modern x86 based computer system running Linux, with the latest 2.2 kernel, the isapnptools package, Symphony driver software, and networking utilities will do.

Proxim Symphony Driver

Proxim Symphony Notes

  1. The Symphony's RF output power is approximately 100 mW (+20 dBm) and can be modified for 200 mW (+23 dBm) output.
  2. The Symphony's receive sensitivity is -77 dBm for 1.6 Mbps and -85 dBm for 800 kbps, typically.
  3. 1.6 Mbps and 800 kbps are the signalling rates, real life data throughput rates will be approximately 320 to 640 kbps. (40 to 80 kBps)
  4. The Symphony's latency times on a strong link will be approximately 20 milliseconds.
  5. You can only have one Symphony per computer due to the fact they are not PnP compliant and all have the same serial number.  Update: It might be possible to have multiple cards, read README.multicards in the driver docs directory for more information.
  6. The Symphony's use 2 level FSK at 800 kbps, and 4 level FSK at 1.6 Mbps FHSS, 79 channels each with about 1 MHz bandwidth.
  7. The default frequency hopping time is 200 milliseconds and is changeable.
  8. Operating temperatures should be around 0°C to 40°C (32°F to 104°F)
  9. The "10 computer limit" is only for the bridge and cordless modem devices.  Under Linux the cards don't have this limit.
  10. The Symphony's default domain is 0 (zero).  This needs to be set in order to operate with any RangeLAN2 devices.
  11. The technical support passwords for the bridge devices are either: buddha or brando
  12. If you are having problems with bad wireless links, try this note on computer case isolation.
  13. View the FCC required EMI tests for the Proxim Symphony.  Includes spectrum analyzer plots.

Reasons Why We Choose The Proxim Symphony

  1. Frequency hopping systems are more resistant to narrowband interference. (microwave ovens)
  2. Frequency hopping systems are able to better overcome multipath problems.
  3. Cost.  You can buy them locally for around $100 new or for $50 on Ebay.  This was also the only cost efficient card available when this project was started.
  4. The ISA and PCI versions are big enough to allow for easy modifications.
  5. Frequency hopping systems are based on conventional narrowband radio technology.  This allows us to use standard test equipment to check the RF sections.  A direct sequence transmitter needs expensive test equipment.
  6. Free T-shirts.
  7. FSK systems are easier to work with and power amplifier requirements are not as demanding.

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