Buying, Installing, and Using a Modem
By the End of This Tutorial, You’ll Able To:
Ø Name the three things your computer needs in order to communicate with another computer over the phone lines
Ø Read a modem ad or box and understand what it says
Ø Compare the speeds of two modems and tell which is faster
Ø Figure out which type of software you need to do what you want to do
Ø Hook up an internal or external modem—and get it to work
Okay, I admit it, the section opener was a tease. I wanted to tell you all the neat things you could do with a modem, so you would start thinking that you simply can’t live without one. I conveniently left out all the complicated information about shopping for a modem, hooking it up, and figuring out what software you need. Now that I’ve sucked you in, I’ll hit you with the hard stuff.To place an order for the Complete Project Material, pay N5,000 to
GTBank (Guaranty Trust Bank)
Account Name – Chudi-Oji Chukwuka
Account No – 0044157183
Then text the name of the Project topic, email address and your names to 08060565721.
Shopping for a Modem
Before you start shopping for a modem, you need a brief lesson in modem-ese, the language of modem ads. Do you think I’m exaggerating? Then read the following ad I lifted from my favorite computer catalogue:
v.34 BOCA 28.8Kbps Modem External
If it’s speed you need, nothing beats the BOCAMODEM 28.8Kbps. It meets Rockwell’s new V.34 standard. You’ll transmit data at 28,800bps up to 115,200bps with data compression and send and receive faxes at 14,400bps. You’ll lower your phone bills and increase productivity with quicker connect times and super-fast delivery of large files. The Boca V.Fast modem is backward-compatible with lower speed V.32bis, V.32, and V.22bis modems. Includes a high-speed, buffered 16C550 UART on-board in the internal.
If you’re in shock, try to calm down. You’ll be able to translate this gobbledygook by the time you finish this section. Take it slow, and read on.
Inside or Out? Internal and External Modems
Modems come in two types: internal and external. An internal modem is a board that plugs into an expansion slot inside your computer. Yeah, you have to flip the hood on your system unit, and plug the thing in. It’s not all that difficult to do, but if you’ve never done it, get a knowledgeable friend to walk you through it for the first time.
An external modem plugs into a serial port (a receptacle) on the back of your computer. To use an external modem, you must have an extra serial port. Look at the back of your system unit to see if it has an extra outlet called COM.
Which is better? Internal modems are less expensive, take up less desk space, and require only one connection (the phone line). If you have an open expansion slot inside your computer, get an internal modem. External modems have a couple advantages: they are easy to install, and most come with indicator lights that show you what the modem is doing (these can help you troubleshoot common problems).
You might see 16550 UART tacked on to a modern ad. Is that good? Well, Windows 3.1 has a hard time transferring modem signals in the background. 16550 UART helps Windows do this more efficiently. Most internal modems have their own 16550 UART support built in, so if you go with an internal modem, don’t worry about it. However, if you’re purchasing an external modem, make sure your serial port uses 16550 UART. (Check the documentation or enter msd at the DOS prompt and press Enter. Click the COM Ports button, and look under UART Chip Used.)
The Hayes modem, made by a company called Hayes Technologies, has set the standard in the modem market. Hayes modems use a set of commands that allow you to tell the modem what you want it to do and how you want it to operate. (For example, to dial the phone number 567-1234, you would enter the Hayes command ATDT followed by the phone number.) This set of commands is called the Hayes command set. When a modem is advertised as being Hayes-compatible, it means that it understands Hayes commands. Make sure the modem is Hayes-compatible, or you may have trouble running the more popular telecommunications software.
Get a Speedy Modem
Modems transfer data at different speeds, commonly referred to as baud rates or bits per second (bps). The higher the baud rate, the faster the modem can transfer data. Common baud rates include 2,400, 9,600, 14,400, and 28,800bps. Although you pay more for a higher baud rate, you save time and decrease your phone bill by purchasing a faster modem. Don’t go with anything slower than a 28,800bps modem, no matter how cheap the 14,400bps modem is.
Baud and Bps – What’s the Difference?
Baud is the maximum number of times a modem can change the signal it sends per second. Bits per second. A modem may send more than one bit of information for each change in the electrical signal. For example, a modem operating at 300 baud may be transferring at 1,200 bps. So if you are comparison shopping, you would do better to compare rates based on bits per second.
V.34bis, V.42bis, and Throughput
Nothing perks up a modem ad like a list of standards: V.34bis, V.42bis, MNP 2 – 4. You don’t know what these standards represent, but you just gotta have them. To understand the standards, keep in mind that they fall in three categories: modulation, data compression, and error correction. (Modulation is a way of sending signals; sort of like AM or FM radio signals, but through the phone lines). The following table lists common standards.
Modem Standards of the Rich and Famous
Category Standard What It Does
Modulation V.22 Transfers up to 1,200bps
V.22bis Transfers up to 2,400bps.
V.32 Transfers up to 9,600bps.
V.32bis Transfers up to 14,400bps.
V.32terbo Transfers up to 19,200bps.
V.34 or V.Fast Transfers up to 28,800bps.
Error Correction MNP 1, 2, 3 Checks for phone line noise and
corrects transmission errors.
MNP4 Checks for transmission errors and
adapts to phone line conditions.
LAPM Prevents transmission errors.
V.42 Combines MNP 2, 3, and 4 with
Data Compression MNP 5 and 7 Compress data 2:1
V.42bis Compresses data 4:1.
Modems that come with data compression can squish data before sending it. This allows the modem to send more data per second. Trouble is, both modems (the caller and receiver) must use the same data compression standard in order for it to work. If you know that you’ll be communicating with another modem using a specific data compression standard, make sure you get a modem with a matching standard. For online services you don’t need to worry too much about data compression.
Oh yeah, and don’t let the term “throughput” confuse you. Throughput is simply a measure of how much data a modem can transfer given its speed and data compression capability. For example, in the ad I mentioned earlier, the throughput was advertised as 115,200bps with data compression. That means that when the modem is operating at maximum speed 28,800bps using V.42 data compression, the modem can transfer data a: 115,200bps. Although conditions rarely allow for this high-speed data transfer, it looks good on paper.
What About the New ISDN and Cable Modems?
The trouble with most modems is that they have to use phone lines, which were designed for voice communications, not data communications. (You know how little useful data is transferred during a typical voice conversation.) Voice is carried over the phone lines by analog (wave) signals, which aren’t the most efficient carriers of digital information.
Currently, 28,800bps modems push the limits of standard phone lines. Even if you have a 28,800bps modem, you’ll usually find that your connection is slightly slower (say 26,400bps or even 14,400bps) because of line noise or some other glitch. If you want to go beyond this speed, you need an ISDN (Integrated Services Digital Network) or cable modem.
ISDN modems use special phone lines to transfer data at up to 128Kbps (128,000bps). That’s over four times faster than a 28,800bps modem! In addition, an ISDN phone line is like having two phone lines. You can carry on a voice conversation on one line and connect to the Internet on the other line (although the connection will be half the speed—64Kbps). If you’re considering an ISDN modem, check out the following:
Ø Call your phone company first. Ask if they offer ISDN service and find out how much it will cost for connecting and monthly fees. This information alone will usually be enough to convince you that you don’t need ISDN service.
Ø Before you buy an external ISDN modem, make sure that you have a super-fast serial port connection or that the modem connects to a parallel port (and you have an open parallel port). Otherwise, the modem will transfer data over the phone lines faster than it can transfer data to and from your computer.
Ø Make sure the modem can handle analog data transfers at 28,800bps. You may still have to establish analog connections with some services.
The newest modems on the market are cable modems, which make a computer “cable ready.” They act like the cable connection on your TV set. And like the cable connection on your TV set, they require you to call the cable company and have a person come out to install the cable service. Because these coaxial cables can carry so much information (30MB per second!), they are ideal for video connections and ±.e Internet. The trouble is that TV cables are made to bring information into your house, not out of it. However, cable companies are working hard to update their lines for two-way communication.
Themodem and communications industries are moving so fast that the new technologies are going to have to play king of the Ml to determine the standard. My advice is to wait until you can pull signals into your computer through an RCA satellite dish.
Flash ROM Is Good
Modem manufacturers are constantly developing new technology to increase data transfer rates. Many of these improvements come in the form of the instructions that tell the modem how to compress and decompress data. These instructions are stored in the modem’s ROM (read-only memory). A flash ROM allows you to update the instructions to take advantage of the new technology. You obtain the ROM update from the modem manufacturer (either on disk or over the phone lines) and install it in your modem. Without flash ROM, you would have to buy a whole new modem.
To Fax or Not To Fax?
Some modems, called fax modems, come equipped with the added capability either to simply send faxes or to both send and receive faxes. Like fully equipped fax machines, a fax/modem allows you to dial a number and transmit pages of text, graphics, and charts to a conventional fax machine, or to another computer that has a fax/modem. You can also use the fax modem to receive incoming calls.
Shop carefully. Many fax/modems are able only to send faxes, not to receive them. If you want to receive faxes, make sure the fax/modem can handle incoming faxes. Also, make sure your modem supports Class 1 and 2 Group III fax machines. Nearly 90 percent of faxes in use today are of the Group III variety.
If you plan on having your computer answer the phone and take messages, make sure the modem offers voice support. Without voice support, your modem can answer the phone, but it can only make annoying screeching noises…which is useful for making telemarketers back off.
Some modems are also designed to handle video calls, sort of like on The Jetsons. However, if modems are too slow to handle simple file transfers, you can imagine how slow they are to transfer video images. Also, you and your friend would both need cameras attached to your computer, to film you while you’re talking, and that’s just too weird.
Do You Need Another Phone Jack for the Modem?
If you already have a phone jack near the computer, but your phone is plugged into it, you don’t need to install an additional jack. Most modems come with two phone jacks: one that connects the modem to the incoming phone line and another one into which you can plug your phone. When you are not using the modem, you use the phone as younormally would. If your modem doesn’t have two phone jacks, you can purchase a split phone connector from an electronics store. The split phone connector allows you to plug both your phone and your modem into the same jack.
If your computer is far from an existing phone jack, get a long phone cable, or have an additional phone jack installed. If you’re good with a screwdriver and pliers (and maybe a drill, hammer, or other instruments of destruction), you can probably do it yourself in less than an hour.
When the Line Is Busy
If your modem and phone are on the same line, your modem will try to answer the phone when it rings. (This drives my wife crazy.) To get around this problem, you can buy a voice/data switch that routes the call to either your computer or your phone. If the incoming call is oneof those high-pitched computer squeals, the switch routes the call to the computer.If the call is a normal phone call, your phone rings so you can pick it up and starttalking.
Installing a Modem
Modem installation varies depending on whether you are installing an internal or external modem. With an internal modem, you must get under the hood of your PC, plug the modem into an open expansion slot, and plug the modem into the phone jack. If you’re a rank beginner, get some experienced person to coach you through it.
Just about anyone can install an external modem. All you have to do is turn off the computer and make three connections:
Ø Modem to serial port Connect the modem to the serial port (usually marked COM) on your computer using a serial cable.
Ø Modem to power source Plug the modem’s power cord into a receptacle on your wall or into your power strip or surge suppressor.
Ø Modem to phone line Connect the modem to the phone jack. This is just like plugging a phone into a phone jack. (You might also want to connect your phone to the modem, as shown here.)
Before You Call
Before you begin using your modem, you might need some additional software. To determine what software you need, ask yourself what you want to do with the modem. The following paragraphs describe some of the common uses for a modem and the type of program required for each use.
Online information servicesIf you want to connect to an online service (such as Prodigy or America Online), you have to purchase a special program and pay the subscription price to the service.
Surf the InternetThis is sort of like connecting to an online service (in fact, you can connect to the Internet through an online service). You can also connect (less expensively) by using a local Internet service provider. The service provider usually equips you with the software you need and any other instructions you need to get started.
Games in two-player modeIf you have a game that allows you to play games in two-player mode using a modem, the program probably contains all the tools you’ll need to play the game over the phone lines. Refer to the user manual that came with the game.
Transfer files between two computers or connect to a bulletin board systemYou will need a communications program. Most modems come with a simple communications program. Windows comes with a program called Terminal (HyperTerminal in Windows 95), which works fine. Your modem probably came with its own communications program, which is usually better than the one in Windows.
Remote computing Say you have a computer at work and one at home. You can purchase a special remote computing program that lets you control your computer at work from your computer at home and vice versa. Try Norton’s pcAnywhere.
“Free” Long Distance CallsIf you heard the buzz about this, that’s just what it is. You can’t just avoid long-distance charges to your pal across the country by placing the call with your modem. You need special software, and an Internet connection. Your friend needs the same special software and Internet connection. Then, you have to call at the same time, go to a special area on the Internet, and find your pal. This isn’t easy.
Bulletin Board System
A bulletin board system (BBS for short) enables a computer to automatically answer the phone when other computers call. The BBS allows the calling computer to copy files to it (upload files) and copy files from it (download files). Although you can purchase a BBS program to set upyour own BBS, most users work with BBSs set up by computer companies andprofessional associations.
Know Your Telecommunications Settings
If you connect your computer to another computer or to an online service, you must make sure both computers are using the same communications settings. Otherwise, errors nay result during data transfer. For example, if one modem is talking at 14,400bps and the other is listening at 2,400bps, it’s likely that some information will get lost. Common communications settings include the following:
Baud rate The transfer rate can be only as fast as the slower of the two modems allows.
COM port The COM port setting tells the telecommunications program where to look for your modem. (The COM port setting applies only to your computer; the settings do not have to be the same on both computers.) If you get a message saying that the program cannot find your modem, try changing the COM port setting.
Parity Tests the integrity of the data sent and received. Common setting is None or No Parity.
Data bits Indicates the number of bits in each transmitted character. Common setting is Eight.
Stop bits Indicates the number of bits used to signal the end of a character. Common setting is One bit.
Duplex Tells the computer whether to send and receive data at the same time (Full), or send data or receive data but not both at the same time (Half). Common setting is Full.
The important thing to remember is that the communications settings must be the same on both computers (although your modem and telecommunications program can adjust most of the settings automatically). Once the settings are right, you can enter a command to have the modem call the other computer. The communications program dials the number and establishes the connection between the two computers.
What Went Wrong?
Rarely do modem communications proceed error free the first time. Any minor problem or wrong setting can cause a major disruption in the communications between your computer and the remote computer.
The Least You Need To Know
The most difficult aspects of telecommunications are in picking out a good modem and setting it up. Once you get the modem working for at least one program, the rest is easy. As you struggle, keep the following in mind:
Ø In order for you to use a modem, you need three things: the modem, a communications program, and a connection to your phone jack.
Ø The speed at which a modem transfers information is measured in bits per second (bps). When shopping for a modem, look for one that transfers data at 28,800bps or faster.
Ø Modems that have fax capabilities can transfer faxes to or from a fax machine or another computer that is equipped with a fax modem.
Ø The telecommunications program you need depends on what you want to do. When you subscribe to an online service, you usually get the program you need in order to connect to the service.To place an order for the Complete Project Material, pay N5,000 to
GTBank (Guaranty Trust Bank)
Account Name – Chudi-Oji Chukwuka
Account No – 0044157183
Then text the name of the Project topic, email address and your names to 08060565721.