A completely wireless Datastorm networkby Don Bradner |
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I use a single laptop whenever I'm not in my office, and I'm rarely in my office anymore. At home I connect wirelessly to a DSL line, but when I'm in my coach I've been tethered to wires. I accepted this as a necessary evil, and I wasn't interested in the one not-uncommon solution, which is to have a separate PC acting as the Datastorm host and network gateway. Issues with where I would put it, power consumption, boot time, etc. kept it from my option list. In June of this year (2003), the Hughes DW4020 gateway became available as a beta for mobile users, and I was the second to sign up for one. If you are not familiar with the 4020, it is a small computer the same size, shape and color as the transmit and receive modems. It runs an embedded linux OS, and has 4 ethernet ports. It boots in about 30 seconds, draws little power, and connects automatically to the Hughes network (assuming the dish is pointed). With the 4020, no computer in the network is running any of the standard Hughes Navigator software. | |
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I immediately added a Linksys WAP-11 access point and began getting my internet connection wirelessly. The wireless connection replaced the old USB connection to the modems, and I immediately began to wish for the ability to disconnect from the serial cable attached to the Datastorm controller. I initially was thinking of an RF serial transceiver at both the computer and the controller. I discarded that idea for several reasons, including a cumbersome device attached to the laptop, and possible signal and interference issues. This wireless control had to be as bulletproof as possible, and available whenever I was connected to the network. Somewhat by accident a ran across a mention of net-to-serial devices, and I was on my way. In the photo at right you see my laptop, running Datastorm administrator, with NO WIRES! (and no doctoring with Photoshop) :) |
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The details: |
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The device I chose is a Moxa nPort 5210, purchased from Neteon in New Jersey. As seen at right, it is about the size of a cigarette pack, and has 3 RJ-45 connectors. One is a standard ethernet connection, and the other 2 are RS-232 serial ports. There is a connector identical to the one used on the Datastorm controller for power, in the range of 12-30 volts. I went with a 2-port controller because it allowed for a connection to the 4020's serial configuration port. I've only had to use that once, but it will be possible now without pulling the modems out and hooking up a null-modem cable. I bought 2 cables, one RJ-45 to 9-pin female, which connects to the 4020, and one RJ-45 to 9-pin male, which connects to the regular Datastorm cable (which is 15-pin at the controller end, and I did not want to have to make up a custom cable). Neteon does not have ordering options for 2 different cables, so I asked for what I wanted in their comment box (ordering online) and they handled it fine. |
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| The nPort comes configured with a default IP of 192.168.127.254. In order to change that, you have to have some way to get into it. My first attempt was to use the serial cable attached to port 1, following the nPort directions. For whatever reason, this was a complete failure. | |
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The next attempt was more successful. I set my laptop's internal IP to 192.168.127.1 and connected using a crossover cable and Hyperterminal. It is possible to have the nPort receive its IP dynamically from the DHCP server in the 4020, but it is easier to have it assigned a static IP, so I set it to 192.168.0.254 (The 4020 gateway is always 192.168.0.1 on a dynamic network). At that point I disconnected the crossover and hooked everthing up in the final configuration as shown at right. The rest of the nPort's software configuration was done using a web connection (the nPort has a built-in web server) and a program called nPort administrator. The two serial ports were given values of Com2 and Com4, with the port going to the 4020 set at 9600,8,n,1 and the Datastorm controller port at 115200,8,n,1. That was it; of course when Datastorm Administrator was run it was not finding the controller and asked to have the serial port set. As soon as I told it to use Com2 it started right up and had no problem with communications. The install was done with the dish stowed, and the photo at the top of this page was taken after a successful find dish. As you can see from the photos, the "communications cabinet" is setup with switches to control power to each of the units, and the cabinet has a wire grate panel to allow adequate ventilation. Not shown is the Linksys AP - it is in another cabinet. |
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| If you have any questions about this, feel free to communicate via the DatastormUsers.com forum or by e-mail (below). | |
19-Jun-13 E-Mail donb@arcatapet.com Site design by Arcata Pet Software