Microsoft

Using infrared communications in Windows 98

Though often overlooked, infrared devices can provide a practical, low-cost method of communication. In this Daily Drill Down, Talainia Posey discusses the basics of infrared communication and how it's supported in Windows 98.


Although infrared communications is fully supported by Windows 98, I don’t know a single person who actually uses this feature. It could be that Windows 98’s infrared capabilities aren’t well publicized, and not enough documentation exists to help support would-be infrared users. In spite of its lack of popularity, it is a very practical and low-cost method for implementing some types of communications. In this Daily Drill Down, I’ll discuss how Windows 98 implements infrared communications.

How do infrared devices work?
Many laptops, PDAs, and some printers contain infrared ports. These ports usually look like a piece of black glass or plastic. Behind the plastic cover, however, are two components. The first is an IED, or Infrared Emitting Diode. This is the same component that’s used in television remotes. An IED functions exactly like an LED (Light Emitting Diode), except that rather than emitting red, yellow, or green light, an IED emits invisible infrared light.

The other component is an infrared receiver. This receiver is identical to the one found in your television set that allows it to receive signals from your remote control. Infrared is used because visible light doesn’t interfere with it. Infrared light behaves exactly the same whether you’re in a bright environment, such as direct sunlight, or in total darkness.

Your infrared device communicates by emitting pulses of infrared light. The infrared receiver on the other device senses these pulses and translates them into binary code. Most infrared-enabled devices have send and receive mechanisms built in. This makes it possible for the device that’s receiving the infrared signal to respond with a confirmation signal, if necessary.

Viewing infrared light in action
Until a couple of years ago, it was impossible for the average computer user to actually see infrared communications in action. Today, however, a wide variety of night-vision devices actually make it possible to see this otherwise invisible light.

If you own a Sony Handycam or a similar night-vision system, you can use it to watch infrared communications as they occur. Simply enable the night vision option and point the camera at any infrared-enabled device. You’ll see extremely bright pulses of light that correspond to the communications taking place.

Infrared devices and networking
The process used by infrared communications is actually very similar to that of traditional networking. In the infrared world, as with the traditional networking world, you must have two devices. The infrared ports take the place of network cards.

Another component in a traditional network is the communications medium. Normally, this is some type of cable. In Infrared communications, however, the medium is the direct line of sight between two devices. Actually, infrared devices don’t have to be lined up exactly opposite each other, just as your television remote doesn’t have to be lined up directly with the sensor on the television to work. Most infrared ports are designed to provide up to a 30-degree tolerance. Keep in mind, though, that the closer the devices are to each other, the better they will work, especially in high-speed applications. This is because factors such as sunlight, fluorescent lights, and some types of background radiation can disrupt communications. These sources of interference aren’t really a factor with your TV, because the signal sent by your remote is relatively slow and is constantly repeated as long as you’re holding down the button. However, when it comes to exchanging data between computers, slow signals and multiple repeats would make for unacceptably slow communications.

In traditional networking, each device on the network must have an independent identification. This is usually made up of a MAC (Media Access Control) address and a computer name. In infrared communications, a MAC address isn’t necessary because you’re beaming the information directly to the destination device instead of placing packets on a line that could be connected to hundreds of different devices. Like a traditional network, however, infrared devices still need a way of identifying one another. As with a traditional network, this is done through a computer name (in the Windows environments anyway).

Finally, traditional networks require at least one protocol. A protocol is a language that the devices on the network use to communicate with each other. Just as humans require a common language (such as English, Spanish, etc.) to communicate with each other, computers require a language such as TCP/IP or IPX/SPX to communicate with each other. The computer must be able to understand what the packets received by its network card mean. That’s what a protocol makes possible.

Infrared communication also uses a protocol. If you look in Control Panel’s Network applet, you’ll see that your infrared device has been installed as a network device just like a traditional network card. When you first install infrared support, the infrared device isn’t bound to any of the existing protocols. This is because infrared communications require a proprietary, unlisted protocol. Some infrared operations do require the use of an additional protocol, however. If you find yourself having to install a traditional protocol for infrared communications, I recommend using NetBEUI since it requires minimal configuration.

What can an infrared port do?
Now that you know how the infrared port in your computer works, you’re probably wondering what you can do with it. The most common use for infrared ports is to transfer files between devices. For example, you can transfer files between a Windows CE device and a desktop PC or between two notebook PCs. Of course, you’re not just limited to these types of transfers. You can transfer files between just about any two devices. You can also use the infrared port to send a print job to an infrared-enabled printer. Finally, you can use an infrared port to establish a serial-style network connection. The speed at which your computer can perform such tasks will depend on which type of infrared port is installed in your devices. Most devices use an SIR (Serial Infrared) port, which is capable of transferring data at 115,200 bps, the equivalent of a serial port. Windows 98 also supports the newer FIR (Fast Infrared) port, which can transfer data at 4 Mbps.

Installing an infrared device
The method that you’ll use to install an infrared device depends on whether or not the device is plug and play compatible (most FIR devices are). If the device is a plug and play device, then simply plug it in and the drivers will load automatically. If the Infrared icon doesn’t automatically appear in Control Panel, press the [F5] key to refresh the view.

If your device isn’t plug and play aware, you have a little more work ahead of you. Begin by opening Control Panel and double-clicking the Add New Hardware icon. Windows 98 will search for plug and play devices and then ask you if you want it to search for new hardware or if you want to install the hardware manually. Select the radio button that corresponds to the option No I Want To Select The Hardware From A List, and click the Next button. On the next screen, you’ll see a long list of device types. Select the Infrared Devices option from the list, and click Next. You’ll now see a summary screen that tells you that you can use an infrared device to send and receive files, print files to an IrDA-compliant printer, or to access a network. Click Next to continue. On the resulting screen, you’ll see a list of manufacturers and infrared devices. Unless you have a specific driver for your device, select Infrared COM Port Or Dongle from the left column and Generic Infrared Serial Port Or Dongle from the column on the right.

After Windows 98 copies some files from your installation media, you’ll be presented with a list of infrared transceivers. If your device is on the list, select it. Otherwise, select the Generic Infrared Port option and click Next. The resulting screen will ask you which serial port you want to assign the device to. Make your selection, and click Next to continue. A summary screen will appear listing the COM and LPT port assignments. If the selections are correct, click Next. If they need to be changed, you can use the Change Ports radio button to make the correction. If you’re unsure of whether or not the options are correct, you’re usually safe using the defaults. Finally, click Finish to complete the installation.

Infrared Monitor
You’ll have to set your infrared options before you can use the infrared port. The primary tool for working with infrared support is Infrared Monitor. You can access Infrared Monitor by opening Control Panel and double-clicking the Infrared icon. You can also access Infrared Monitor by double-clicking its icon in the system tray. In the following sections, I discuss each of Infrared Monitor’s options. You access them through the Status, Options, Preferences, and Identification tabs.

Status
When you first open Infrared Monitor, you’ll see the Status tab. Although you can’t actually configure anything through the Status tab, it’s a nice place to get an instant status report on the infrared device without having to go through Device Manager. As you can see in Figure A, the Status tab can even tell you if the device has been disabled.

Figure A
Infrared Monitor’s Status tab reports whether the infrared device is disabled or enabled.


Options
When you select the Options tab for the first time, all choices except Enable Infrared Communication are grayed out. Once you select Enable, all of the other options will be available for configuration, as shown in Figure B.

Figure B
The Options tab allows you to specify how your computer communicates with other infrared devices.


The next option, Search For And Provide Status For Other Devices In Range, activates this search. This choice adds CPU activity, however, so power-conscious mobile users might want to disable it.

The Options tab also allows you to set whether Windows will automatically install the software for any plug and play infrared devices that it detects. This option can be very handy if you’re not sure of exactly how to set up communications between two devices.

To help tune infrared communications, you can limit the connection speed by checking that option. This capability is handy if you experience poor communications. Slowing down communications makes for a more reliable link.

The final feature on this tab is the Restore Defaults button, which is always useful if you decide to monkey around with the settings and accidentally screw something up.

Preferences
There are three options on the Preferences tab plus a Restore Defaults button. These options are Display Infrared Icon In Taskbar, Open Infrared Monitor For Interrupted Communications, and Play Sounds For Devices In Range And Interrupted Communications.

Enabling the Display Infrared Icon In Taskbar option gives you more than quick access to Infrared Monitor. The icon itself changes to reflect the status of the infrared port. This can be a big timesaver, because you don’t have to open Infrared Monitor.

If you tend to have communications problems, Enabling Open Infrared Monitor For Interrupted Communications can save you time. Having the monitor pop up when communications are interrupted lets you quickly fine-tune the communications problem and get back to business.

The next option sets up Windows to play a sound if it detects another infrared device or if communications are interrupted. I love this option, because I’ve been in situations in which I’m trying to transfer a large file, and I’ll turn my back to work on something else because the process takes so long. An hour later, I’ll glance at the screen and see that communications have stopped. By setting up Windows to play a warning sound, you’ll know the instant a failure occurs, even if you’re not looking at the screen.

Identification
I mentioned earlier that infrared communications in Windows 98 require you to define a computer name. The Identification tab, shown in Figure C, allows you to do this. It also allows you to provide an optional description of the device. The computer name and description found on this tab correspond to those found in Control Panel’s Network applet.

Figure C
A computer name is required for infrared communications.


Using infrared devices to transfer files
Moving files between infrared devices might work differently from devices to which you’ve been accustomed. If you open My Computer, you’ll notice that an icon has been added called Infrared Recipient. You can use this icon to transfer files to another computer. To do so, double-click the Infrared Recipient icon, which will open the Infrared Transfer dialog box. This dialog box will list all of the infrared devices within range. Select the device that you want to send the files to, and click the Send Files button. Windows will then allow you to select the files that you want to send. Select your files, and then click the Open button.

The first time that you use the infrared method to transfer files, Windows will create a folder on the recipient machine called My Received Files. All transferred files will be placed in this folder.

Infrared printing
It’s tough to provide an exact method for infrared printing since there are a lot of infrared printers out there. Here’s a general description of a procedure that you might use, however. Begin by bringing the printer within range of a computer that has infrared communications enabled. If the printer is plug and play capable and you’ve set the appropriate options, Windows may automatically detect the printer and load the driver. Otherwise, you’ll have to manually load the driver. Through the course of loading it, Windows will set the infrared port as a virtual parallel port. This means that you’ll be able to print to an infrared port just as you would any normal parallel port.

If you’d like to take advantage of infrared printing but don’t have an infrared-compatible printer, you can still do so by adding an infrared port to your existing printer. Several add-on devices exist, such as the JetEye Infrared Printer Port ESI-9580 from Extended Systems.

As I’ve shown in this Daily Drill Down, Windows 98 infrared communications works similarly to any other network communications. It can be used to print, to transfer files between computers and Windows CE devices, and for networking. Installing infrared capability isn’t difficult, and troubleshooting is fairly easy as well. If you haven’t yet made use of this helpful feature of Windows 98, you might want to consider it.
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