by R. K. Bloom

Building a wireless network based on Ricochet, Bluetooth and IEEE 802.11b

Building a wireless network based on Ricochet, Bluetooth and IEEE 802.11b

Original: Dansdata

The development of wireless technology is the same way as the development of wired networks.

First, they were expensive and little known. Small companies and home users can not even dream about them. But it is quite normal, since they would still require two years of training to create a WLAN.

The first relatively cheap WLAN products have already appeared, but they were not good enough. For example, these adapters, as Diamond

Homefree WLAN had a capacity of only one or two Mbit / s (or less), and it turned out, so that they work according to the normal only in those situations where it is possible to do it, and the usual cables.

Today, wireless networks are emerging to a wide market. Ask the user to configure how easy Apple hardware IEEE 802.11b WLAN, solutions for the PC are slightly more complicated to configure. Or at least, should not be difficult.

Speaking of the WLAN today, assuming youre referring to 802.11b, also known as “Wi-Fi”. Easily one can say that this

Standard is the most popular, it has a reasonable price for the equipment and the maximum throughput of 11 Mbit / s. Although there are other standards for wireless networks. Equipment, two of them in comparison to the hardware 802.11b. First – it is the cheapest.

Ricochet Modem

The company has launched a Metricom Ricochet – a network of wireless Internet access in various U.S. cities, then they handed Internet providers responsibilities to other companies, but a network of support for yourself. Unfortunately, the paradigm of profit turned out to be wrong, and they went bankrupt in 2001.

The network used Ricochet wireless modems operating in 900 MHz band. With the modem was all right, except for the maximum

distance, but Metricom has established a lot of repeaters, which created a large enough coverage area. The company kicked the bucket, routers stopped, modems were unnecessary. At least for the majority.

Here is shown a pair of modems Ricochet “GS” – the latest and the best of the series. They operate at a speed of 128 kbit / s, as well as other modems in a series of Ricochet GS. Modems previous series have a lower speed. We purchased this “couple” via eBay for $ 100. Plus shipping, plus the power supply on the 240 instead of 110 in the U.S., with which they come.

The cheapest network adapters 802.11b standard are approximately 70 to $ 100 apiece. You can find a PCI 802.11b “adapters” for about $ 50, but its just Bus Converters PCI-PCMCIA. They allow you to connect 802.11b adapter for the laptop to the PC, which for this, you will still have to buy.

One of the modems pictured above has a 9-pin connector to the serial port on the second – USB. In fact, you can use GS in either mode …

… because they come with two cables that connect to the very micro-port on the back of the unit. To connect via USB you will need a driver using a serial connection – no. It is obvious that the USB allows you to reach speeds well above 128 kbit / s, but we do not succeed, and you also do not expect this rate, if any significant distance using a standard antenna.

In modem GT / GS has built-in battery, which is enough capacity for five hours. The distance depends on how much he charged. Provided that with him all right, these modems work fine with laptops, does not affect the laptop battery.

Everything of value that was in Ricochet, bought Aerie Networks, which is really done much to fulfill his promise of reviving the network. But you do not have to be in range of a network to use the modem Ricochet. In fact, you do not need routers to manage the connection, if you just want to make a connection between two modems.

In Russia, ten thousand miles away from where ever had a network of Ricochet, we think, quite far from “civilization.”

Two Ricochet modem can connect with each other in a point-to-point mode, and run like any other modem, because the computer that is connected to a modem, does not see the difference. For such connections you need to specify a set number, which is written on a label stuck to the bottom of the other modem. It will look like this 03-1234-5678, with the lines, too, must be specified. If the other modem is configured to automatically answer, we can only tell the computer “CALL”, just like an ordinary modem, and then the normal connection is established. Just a quick, any significant delay in establishing the connection between the Ricochet modem does not.

In Ricochet modem is also a mode of “star”, which allows them to create something resembling a WLAN, what

Point-to-point connection, but the possibility to set up such an implementation does not. Although Linux fans can go for it here.

Ricochet modems have a few limitations. Of course, the point-to-point – the most serious of them. If you need a complete WLAN modems built on Ricochet, then it will have to spend a lot more effort than some believe.

A bit of speed. When using a USB or serial port, no matter what you do, the speed will not be higher than 115 200 bits / s, which is not realistic to quickly modems using telephone lines, but terribly slow compared to any Ethernet network or 802.11b. Subtract from this service data, and find that you can give ten kilobytes of data per second, or slightly more.

Response time is also not happy. About 70 ms, with typical differences caused by the radio data system, which is used by modems (which means that they are neither just a modem or cable modem). With point-to-point connection established between two modems Ricochet, you can play games, getting a lot more fun than using a conventional modem, but the difference is not very noticeable.

So what are they good?

As mentioned above, both the modem have an attractive price. You can order them on eBuy. Both the modem, purchased by us, were in perfect condition, was also included in the disc is already out of date drivers from Metricom. Windows XP users will not have to search for the driver, he is there, users of other versions will have to go hunting for drivers, for example, here. Of course, you can use the modem in a sequential mode. They work with anything that supports the RS-232, in this mode, no special drivers are required.

This can be explained by the fact that Ricochet modems use standard AT commands – with some oddities, but working without distortion.

So you can configure them to work with virtually any software easily. This is something akin to an ancient, Ricochet modems are just saying “ERROR” (ERROR), whenever something goes wrong, and give no clue about the cause of the error, but those

who are familiar with AT & F from its ATA not see any problem in this.

Read one of the online guides – full version Metricom AT commands can be found here, first you will be much to ponder.

Among the features supported by the modem Ricochet, is the creation of Virtual Private Networks (VPN). Of course, this decision will not be fast as lightning, but it will be faster than using a conventional dialup modem, and much faster than using even slower GSM phone with a transfer rate of 9600 bit / s. Do not even mention the cost.

This does not mean that Windows will not let you in every possible way to establish a remote connection, making the search for alternate routes, but no more difficult than usual.

Although, you have to be within reach.

Desyatisantimetrovaya flexible antenna provides a maximum distance of a mile in the line of sight, but the use of a range of 900 MHz suggests that this distance is significantly reduced when the signal passes through something more dense than air, so in fact the radius of action is not so much . It strongly depends on the location and position of the antenna, and probably corresponds to the coin on a map than a circular track on a coffee mug.

You can significantly improve the situation by using a different antenna. This is not a five-minute thing, but you do not need

perform soldering. Wires are connected to the antenna connector inside the Sub-SubMiniature (SSMT) (see PDF here). SSMT – its a little-known standard, but the connectors and cables are widely used by large manufacturers of electronics, so do not take a genius to connect the different directional antenna to a standard connector, using which you can connect on an impressive range.

Probably some Ricochet modems are a strange problem with the server name (see here), but our models have worked well.

Secure connections Ricochet is quite sufficient for most users. Here we are talking about security as security

something obscure, though, the attacker can sniff the packets Ricochet easily. But if youre in a country where the modems

Ricochet is never sold, you can be sure that no novice hacker, sitting in a car near your office, can not

read your mail.

In comparison with most networks 802.11b, Ricochet connection resistance can be compared with armored train. 802.11b can be highly protected, but because it is used by most, its like that and leave the Ethernet cables hanging from the windows of the label, “Please do not listen to us.” Elaborate on this later.

A little more information about configuring the Ricochet can be found here. Quite a lot of information about Ricochet modems under Linux can be found here.