With the advent of broadband access to the internet, you might think that modems have become passe. That's just not the case, as a large majority of users still rely on dial-up service to connect to the internet. However, there are fewer choices in aftermarket modems today simply because virtually all new PCs include an internal modem as standard equipment.
As with all computer and electronics equipment, modems can go bad and may need to be replaced. Modems for use with handheld PCs and PDAs are becoming more widespread. With more Palm and Handspring Visor users wanting access to the internet, e-mail, and other information, these modems are enjoying great popularity.
Modems for desktop PCs come in internal and external models. Most internal models today require a PCI expansion slot. External modems generally require a USB port and operating system support for this feature (Windows 98/Me, Windows 2000/NT, Windows XP, or Mac OS.) Older external models are still available for those who prefer to use a serial port.
All modems these days meet the V.90 standard, which defines operations at 56Kbps. Be aware that this speed is misleading. Because of FCC restrictions on the amount of voltage a modem can put on the line, even a "56K" modem has a speed limit of 53Kbps (with most modems averaging speeds from 40Kbps to 50Kbps). That maximum speed is only in one direction, downloading, and many times, connections are made at a much slower rate. Uploading is performed at 33Kbps at best. A new standard called V.92 has recently been approved, and when implemented by the ISPs (Internet service providers), it will raise the upload speed to as fast as 43Kbps.
Virtually all modems include fax capability. This lets you send and receive faxes using your PC, eliminating the need for a fax machine. Because almost no difference exists in the basic functionality between modems today, manufacturers have started adding special features, such as the ability to send voice messages to other users while communicating online or to automatically differentiate between voice, fax, and data calls.
If you are buying a modem for a laptop, there are two additional features you might want to consider. One is the ability of some laptop PC Card modems to connect to a cellular telephone. Not all modems offer this capability, and even those that do require specific phone models. Another nice feature in PC Card-format modems is built-in jacks that eliminate the need for special connector cables. Wireless modems for laptops or PDAs are also gaining in popularity, although you'll have to stay within a coverage area to maintain your connection.
Broadband internet access methods, such as cable and DSL, require a different type of device. Cable and DSL "modems" do not work the same way as a standard V.90 modem, and most need to be matched to the specific vendor offering the service. You can go into a computer store and purchase a modem for DSL access, but unless it's the one specified by the DSL provider, it might not work.
How to Shop
First, consider whether you want an internal or external modem. External modems require an available port to plug into, but they're easier to install and they offer handy status lights. Internal modems require a free slot inside your PC, and are generally a bit less expensive. Of course, if you use a laptop, you'll want to choose a PC Card modem for maximum portability.
If you're investigating alternative high-speed technologies such as DSL or cable modems, contact your local telephone or cable company before buying equipment. Different localities use different standards, and you'll need to buy equipment that is compatible with your local system.
Monday, May 18, 2009
Thursday, May 14, 2009
What Kind of Modems Should I Buy?
e have always recommended external modems. In the past, the main reasons for this were that:
* They can be connected to any kind of computer that has a serial port.
* You can monitor the lights and speaker sounds for troubleshooting.
* They don't cause interrupt conflicts or address confusion, as internal modems almost always do.
In recent times, the reasons to stick with external modems are all the more compelling:
* Almost any recent-model modem is bound to have bugs and defects. Therefore it is better to keep it outside your PC, where it can't affect the internal bus, configuration, or interrupt structure of your computer.
* An external modems can be turned off and on to return it to its power-up configuration, as is often necessary when the modem becomes hopelessly confused. Internal modems can be power cycled only by turning your whole computer off and on.
* External modems are almost never "controllerless". To the best of our knowledge, all RPI modems, Winmodems, and other "software assisted" modems are internal PC modems.
* External modems are never "Plug and Play". Plug and Play modems need special OS-specific loaders to be initialized correctly. They can't be used with DOS applications, even in a Windows 95 DOS window. To the best of our knowledge they work only in Windows 95/98, and maybe to some degree also in Linux through the isapnptools software.
We do not recommend or endorse any particular brand of modem. However, we do recommend the following attributes:
* It should be external rather than internal. The extra price is worth it.
* It should follow established ITU-T (formerly CCITT) standards like V.32bis, V.34, V.90, V.42, and V.42bis. If a modem claims to "exceed" standards or "set" standards, beware; it is unlikely to interoperate correctly, or at all, with modems from other manufacturers.
* It must not depend on operating-system-specific drivers or loaders for any of its signal processing, modulation, error-correction, or compression functions. The operating system should be able to make full use of it through its serial-port driver, with the application providing the interface to the modem's command language. Thus you should be able to change or upgrade operating systems without losing the ability to use your modem.
Read the box carefully before buying.
56K modems are designed for only one purpose: to dial up an Internet Service Provider (ISP) that offers 56K service and has a digital connection to the telephone network. If they don't work for other purposes, this is not surprising, since they were not designed for any other purpose.
V.90 is the recently approved ITU-T standard 56K method, whereas X2 and K56flex are competing proprietary methods that preceded the standard. While V.90 is based on the other two, it does not include either one of them, and is only just now appearing on the market.
Basic connection problems can occur if:
* There is more than one analog segment (and therefore more than one analog/digital conversion point) in the telephone circuit between two 56K modems. Of course, you have no control over this. But it is likely if you are calling any host or service that does not have a direct digital link to the phone network. It might also be the case if you are calling out from a PBX, which can involve multiple A/D D/A conversions.
* There is only one analog segment, but it is too long or too noisy.
* Your modem tickles bugs in the other modem, or vice versa.
* Your modem and the other modem (which might or might not be a 56K modem) can not negotiate a common modulation or protocol. It takes more memory than most modems have to accommodate one or two 56K "standards" plus all the others (v.34 and below) and so essential fallback procedures might be lacking.
In theory, the modems should be able to recover from such situations automatically, and agree upon a lower modulation and connection speed. In practice, sometimes the modems become "frozen" or disconnect entirely. The most common complaint is that the modem makes the connection, but there is only a "blue screen" on the other end. That is, the modems are connected, the local modem reports carrier, but no characters are transmitted.
Performance is a totally separate question, and generally hinges upon the specific pair of modems and the connection between them.
* They can be connected to any kind of computer that has a serial port.
* You can monitor the lights and speaker sounds for troubleshooting.
* They don't cause interrupt conflicts or address confusion, as internal modems almost always do.
In recent times, the reasons to stick with external modems are all the more compelling:
* Almost any recent-model modem is bound to have bugs and defects. Therefore it is better to keep it outside your PC, where it can't affect the internal bus, configuration, or interrupt structure of your computer.
* An external modems can be turned off and on to return it to its power-up configuration, as is often necessary when the modem becomes hopelessly confused. Internal modems can be power cycled only by turning your whole computer off and on.
* External modems are almost never "controllerless". To the best of our knowledge, all RPI modems, Winmodems, and other "software assisted" modems are internal PC modems.
* External modems are never "Plug and Play". Plug and Play modems need special OS-specific loaders to be initialized correctly. They can't be used with DOS applications, even in a Windows 95 DOS window. To the best of our knowledge they work only in Windows 95/98, and maybe to some degree also in Linux through the isapnptools software.
We do not recommend or endorse any particular brand of modem. However, we do recommend the following attributes:
* It should be external rather than internal. The extra price is worth it.
* It should follow established ITU-T (formerly CCITT) standards like V.32bis, V.34, V.90, V.42, and V.42bis. If a modem claims to "exceed" standards or "set" standards, beware; it is unlikely to interoperate correctly, or at all, with modems from other manufacturers.
* It must not depend on operating-system-specific drivers or loaders for any of its signal processing, modulation, error-correction, or compression functions. The operating system should be able to make full use of it through its serial-port driver, with the application providing the interface to the modem's command language. Thus you should be able to change or upgrade operating systems without losing the ability to use your modem.
Read the box carefully before buying.
56K modems are designed for only one purpose: to dial up an Internet Service Provider (ISP) that offers 56K service and has a digital connection to the telephone network. If they don't work for other purposes, this is not surprising, since they were not designed for any other purpose.
V.90 is the recently approved ITU-T standard 56K method, whereas X2 and K56flex are competing proprietary methods that preceded the standard. While V.90 is based on the other two, it does not include either one of them, and is only just now appearing on the market.
Basic connection problems can occur if:
* There is more than one analog segment (and therefore more than one analog/digital conversion point) in the telephone circuit between two 56K modems. Of course, you have no control over this. But it is likely if you are calling any host or service that does not have a direct digital link to the phone network. It might also be the case if you are calling out from a PBX, which can involve multiple A/D D/A conversions.
* There is only one analog segment, but it is too long or too noisy.
* Your modem tickles bugs in the other modem, or vice versa.
* Your modem and the other modem (which might or might not be a 56K modem) can not negotiate a common modulation or protocol. It takes more memory than most modems have to accommodate one or two 56K "standards" plus all the others (v.34 and below) and so essential fallback procedures might be lacking.
In theory, the modems should be able to recover from such situations automatically, and agree upon a lower modulation and connection speed. In practice, sometimes the modems become "frozen" or disconnect entirely. The most common complaint is that the modem makes the connection, but there is only a "blue screen" on the other end. That is, the modems are connected, the local modem reports carrier, but no characters are transmitted.
Performance is a totally separate question, and generally hinges upon the specific pair of modems and the connection between them.
Buying Cellular Modems
A cellular modem will let you and your laptop tap into the high-speed wireless 3G networks that blanket the U.S., so you can surf the Web and download files at broadband speeds anywhere you can use your cell phone. Over the past couple of years, modems have become more compact, compatible, and flexible, but you do have to pay for the device itself along with cellular broadband service that'll cost you from $40 to $60 a month. Still, if you want to get online with a fast network that's more ubiquitous than Wi-Fi, here are some tips to keep in mind when picking a carrier and a device.
Understand the Limits
Cellular broadband can't replace good old residential broadband, because every wireless carrier has some sort of a data limit, typically 5GB per month. That's enough for basic Web surfing and e-mail, but not much more. Pop that cap and most service providers will give you a warning; keep going and you'll probably get cut off or charged insanely high overage rates. (If Cricket is your provider, however, it just throttles down your speed for the remainder of the month.) So if you intend to pump a lot of data through your connection, cellular broadband probably isn't for you.
Balancing Price, Speed, and Coverage
AT&T, Sprint, T-Mobile, and Verizon Wireless each charge $60 a month for a cellular modem subscription, while Cricket charges $40 per month and requires no contract. The devices themselves range in price from free up to around $300, depending on what kind of deal you can get when you sign a service contract.
So just how fast is 3G? In our tests, we found that the city you're in matters more than the technology you're using. Depending on various network factors, you can expect download speeds between 800 kilobits per second and 2.5 megabits per second and upload speeds between 300 Kbps and 800 Kbps. 3G doesn't cover the whole nation (it's absent particularly in lower-population areas); if it's not available your connection will drop to 2G, with download speeds of around 100 Kbps for Sprint and Verizon and 120 to 200 Kbps for AT&T and T-Mobile.
AT&T offers 3G coverage in the form of HSDPA 3.6 in portions of 42 states plus Washington, D.C., and Puerto Rico; the carrier is also testing a faster download system, HSDPA 7.2, which should be released in large markets later this year. T-Mobile offers HSDPA 3.6 in portions of 21 states plus Washington D.C.
Sprint, Verizon, and Cricket use EV-DO Rev A. Verizon's 3G coverage is much more solid than the other national carriers', especially in many rural areas and large parts of the northeastern U.S.
Sprint's 3G coverage isn't quite as good as Verizon's. But Sprint is the first carrier to offer 4G (aka WiMAX), the fastest available cell broadband service, with transfer rates of up to 8 Mbps—although it's currently available only in Baltimore and in Portland, Oregon. If you're interested in WiMAX, currently you have one choice: the Sprint 3G/4G USB Modem U300, the only modem that works with both WiMAX and 3G networks (and it works only in Baltimore).
Cricket isn't available nationwide; you'll find it primarily in medium-size and large cities. Cricket uses both EV-DO Rev A and the slower EV-DO Rev 0, which deliver speeds of around 450 to 700 Kbps down and 150 Kbps up. You'll need to check with the carrier as to whether you're in a Rev 0 or a Rev A city, as there's no indication of the difference on Cricket's Web site.
Can't get coverage where you live? WISPs (wireless ISPs) generally use larger, home-based modems, but they're available in many (though not all) small towns where traditional broadband or cellular service can't be found. What's more, they don't carry 5GB limits.
Add a Modem, Embed, or Tether?
If you decide to make the 3G jump, cellular modems aren't the only option. You'll find a wide range of PCs and netbooks with integrated 3G from almost every manufacturer, save for Apple. In our tests, these devices typically deliver solid speed and reception—but of course, you've got to buy a new system, and you may be yoked to one wireless carrier for the life of the PC.
You can also use your existing cell phone as your laptop's modem through a process called "tethering." Not terribly convenient, and often difficult to set up, tethering doesn't require that you buy anything extra or subscribe to a separate service plan, and monthly supplemental charges are typically less than dedicated modem plans. On our tests, tethered phone connections are generally slightly slower than dedicated modem connections.
On Verizon Wireless, the tethering supplement costs $60 per month for feature phones and between $15 and $30 for smartphones, depending on your service plan. (Check out the full list of Verizon tether-ready phones.) With AT&T, smartphones other than the iPhone are generally tetherable, and you'll pay $30 on top of a personal PDA plan. On Sprint, it's $15 on top of many of the $30-or-higher monthly data plans. To find out if your Sprint phone has tethering abilities, select your phone at the carrier's site, and check to see if Sprint SmartView software is available for your model. Cricket doesn't offer tethering, and while it's possible to use your phone as a modem on T-Mobile, it's not officially supported, so you run the risk of getting cut off at any time.
You've Settled on a Modem, Now Choose a Form Factor
There are three varieties of 3G modems: USB devices, PC Cards, and ExpressCards. The latter two are convenient because you put one into a slot on your laptop and leave it there—but, of course, your PC needs to have the right slot. USB modems are more flexible, because every system has at least one USB port, you can plug a modem into one and not have to worry about switching modems when you switch PCs.
When it comes to performance, we haven't found much of a difference between cards and USB modems. In fact, we've found that the same device in the same place can get different speeds at different times. This is usually because of the modem's chipset and built-in antenna configuration—unique factors in every model. We test modems by trying a sequence of uploads and downloads from multiple sites at least seven times, at different times of day, and in different locations. Only when averaged out over multiple tests do trends become clear. The fastest modems available for each carrier typically receive our Editors' Choice.
Once you've decided which type of modem to get, you might want to consider extra features. Some devices come with built-in microSD card readers for accessing the memory card from your phone, or built-in GPS, so you can use your laptop as a portable navigator.
You'll also find models that let you connect an external antenna. If you live, work, or travel in areas where the 3G signal is consistently weaker than about -90 dBm (decibels above 1 milliwatt; there's a signal meter in your connection manager software that will provide this information), you'll get a big boost from an external antenna or amplifier. Unfortunately, antennas are pretty large, and toting one can be cumbersome.
Mac & Linux Compatibility
Make sure your modem is compatible with your PC's operating system. Every modem offered by AT&T, Sprint, T-Mobile, Verizon Wireless, and Cricket works with Windows XP and Vista, and most modems available today work with Mac OS 10.5 (Sprint's 3G/4G USB Modem U300 and T-Mobile's first modem, the webConnect USB Laptop Stick are notable exceptions). The Novatel Ovation U760 for Sprint and Verizon, and the Sierra Wireless 598U and Novatel Merlin EX720 for Sprint are officially Linux-compatible, and unofficial Linux drivers for AT&T's Sierra and Option cards are also available from the manufacturers' Web sites.
Beware: Overseas Surfing Will Cost You
Traveling abroad? Taking your laptop and modem along isn't as easy as it might seem. AT&T modems will work almost everywhere in the world, but if you're leaving the country, you should get a temporary data add-on to your service plan. You can opt for from 20MB to 200MB of data usage ($25 to $229 per month). If you don't have one of these plans, you'll be charged up to $20 per megabyte (that's MB, not GB) for data overseas. Ouch. T-Mobile modems also work abroad, but they don't have add-on plans available—it's just $15 per megabyte outside the U.S. and Canada.
If you're with Verizon, your modem will work in Canada, and the company will sell you a global ExpressCard that works with a $129.99-per-month plan for use in other countries. But you'll need a laptop with an ExpressCard slot. Otherwise, you're stuck with a $20-per-megabyte rate. Sprint will also sell you special international cards and modems but offers no overseas data roaming plan; if you go to Europe, for instance, you'll pay a flat rate of $16 per megabyte.
If you need Internet access outside the U.S., use your hotel Wi-Fi, hunt down hot spots or use a BlackBerry with an international data plan, which is much less expensive than a cellular card plan.
Understand the Limits
Cellular broadband can't replace good old residential broadband, because every wireless carrier has some sort of a data limit, typically 5GB per month. That's enough for basic Web surfing and e-mail, but not much more. Pop that cap and most service providers will give you a warning; keep going and you'll probably get cut off or charged insanely high overage rates. (If Cricket is your provider, however, it just throttles down your speed for the remainder of the month.) So if you intend to pump a lot of data through your connection, cellular broadband probably isn't for you.
Balancing Price, Speed, and Coverage
AT&T, Sprint, T-Mobile, and Verizon Wireless each charge $60 a month for a cellular modem subscription, while Cricket charges $40 per month and requires no contract. The devices themselves range in price from free up to around $300, depending on what kind of deal you can get when you sign a service contract.
So just how fast is 3G? In our tests, we found that the city you're in matters more than the technology you're using. Depending on various network factors, you can expect download speeds between 800 kilobits per second and 2.5 megabits per second and upload speeds between 300 Kbps and 800 Kbps. 3G doesn't cover the whole nation (it's absent particularly in lower-population areas); if it's not available your connection will drop to 2G, with download speeds of around 100 Kbps for Sprint and Verizon and 120 to 200 Kbps for AT&T and T-Mobile.
AT&T offers 3G coverage in the form of HSDPA 3.6 in portions of 42 states plus Washington, D.C., and Puerto Rico; the carrier is also testing a faster download system, HSDPA 7.2, which should be released in large markets later this year. T-Mobile offers HSDPA 3.6 in portions of 21 states plus Washington D.C.
Sprint, Verizon, and Cricket use EV-DO Rev A. Verizon's 3G coverage is much more solid than the other national carriers', especially in many rural areas and large parts of the northeastern U.S.
Sprint's 3G coverage isn't quite as good as Verizon's. But Sprint is the first carrier to offer 4G (aka WiMAX), the fastest available cell broadband service, with transfer rates of up to 8 Mbps—although it's currently available only in Baltimore and in Portland, Oregon. If you're interested in WiMAX, currently you have one choice: the Sprint 3G/4G USB Modem U300, the only modem that works with both WiMAX and 3G networks (and it works only in Baltimore).
Cricket isn't available nationwide; you'll find it primarily in medium-size and large cities. Cricket uses both EV-DO Rev A and the slower EV-DO Rev 0, which deliver speeds of around 450 to 700 Kbps down and 150 Kbps up. You'll need to check with the carrier as to whether you're in a Rev 0 or a Rev A city, as there's no indication of the difference on Cricket's Web site.
Can't get coverage where you live? WISPs (wireless ISPs) generally use larger, home-based modems, but they're available in many (though not all) small towns where traditional broadband or cellular service can't be found. What's more, they don't carry 5GB limits.
Add a Modem, Embed, or Tether?
If you decide to make the 3G jump, cellular modems aren't the only option. You'll find a wide range of PCs and netbooks with integrated 3G from almost every manufacturer, save for Apple. In our tests, these devices typically deliver solid speed and reception—but of course, you've got to buy a new system, and you may be yoked to one wireless carrier for the life of the PC.
You can also use your existing cell phone as your laptop's modem through a process called "tethering." Not terribly convenient, and often difficult to set up, tethering doesn't require that you buy anything extra or subscribe to a separate service plan, and monthly supplemental charges are typically less than dedicated modem plans. On our tests, tethered phone connections are generally slightly slower than dedicated modem connections.
On Verizon Wireless, the tethering supplement costs $60 per month for feature phones and between $15 and $30 for smartphones, depending on your service plan. (Check out the full list of Verizon tether-ready phones.) With AT&T, smartphones other than the iPhone are generally tetherable, and you'll pay $30 on top of a personal PDA plan. On Sprint, it's $15 on top of many of the $30-or-higher monthly data plans. To find out if your Sprint phone has tethering abilities, select your phone at the carrier's site, and check to see if Sprint SmartView software is available for your model. Cricket doesn't offer tethering, and while it's possible to use your phone as a modem on T-Mobile, it's not officially supported, so you run the risk of getting cut off at any time.
You've Settled on a Modem, Now Choose a Form Factor
There are three varieties of 3G modems: USB devices, PC Cards, and ExpressCards. The latter two are convenient because you put one into a slot on your laptop and leave it there—but, of course, your PC needs to have the right slot. USB modems are more flexible, because every system has at least one USB port, you can plug a modem into one and not have to worry about switching modems when you switch PCs.
When it comes to performance, we haven't found much of a difference between cards and USB modems. In fact, we've found that the same device in the same place can get different speeds at different times. This is usually because of the modem's chipset and built-in antenna configuration—unique factors in every model. We test modems by trying a sequence of uploads and downloads from multiple sites at least seven times, at different times of day, and in different locations. Only when averaged out over multiple tests do trends become clear. The fastest modems available for each carrier typically receive our Editors' Choice.
Once you've decided which type of modem to get, you might want to consider extra features. Some devices come with built-in microSD card readers for accessing the memory card from your phone, or built-in GPS, so you can use your laptop as a portable navigator.
You'll also find models that let you connect an external antenna. If you live, work, or travel in areas where the 3G signal is consistently weaker than about -90 dBm (decibels above 1 milliwatt; there's a signal meter in your connection manager software that will provide this information), you'll get a big boost from an external antenna or amplifier. Unfortunately, antennas are pretty large, and toting one can be cumbersome.
Mac & Linux Compatibility
Make sure your modem is compatible with your PC's operating system. Every modem offered by AT&T, Sprint, T-Mobile, Verizon Wireless, and Cricket works with Windows XP and Vista, and most modems available today work with Mac OS 10.5 (Sprint's 3G/4G USB Modem U300 and T-Mobile's first modem, the webConnect USB Laptop Stick are notable exceptions). The Novatel Ovation U760 for Sprint and Verizon, and the Sierra Wireless 598U and Novatel Merlin EX720 for Sprint are officially Linux-compatible, and unofficial Linux drivers for AT&T's Sierra and Option cards are also available from the manufacturers' Web sites.
Beware: Overseas Surfing Will Cost You
Traveling abroad? Taking your laptop and modem along isn't as easy as it might seem. AT&T modems will work almost everywhere in the world, but if you're leaving the country, you should get a temporary data add-on to your service plan. You can opt for from 20MB to 200MB of data usage ($25 to $229 per month). If you don't have one of these plans, you'll be charged up to $20 per megabyte (that's MB, not GB) for data overseas. Ouch. T-Mobile modems also work abroad, but they don't have add-on plans available—it's just $15 per megabyte outside the U.S. and Canada.
If you're with Verizon, your modem will work in Canada, and the company will sell you a global ExpressCard that works with a $129.99-per-month plan for use in other countries. But you'll need a laptop with an ExpressCard slot. Otherwise, you're stuck with a $20-per-megabyte rate. Sprint will also sell you special international cards and modems but offers no overseas data roaming plan; if you go to Europe, for instance, you'll pay a flat rate of $16 per megabyte.
If you need Internet access outside the U.S., use your hotel Wi-Fi, hunt down hot spots or use a BlackBerry with an international data plan, which is much less expensive than a cellular card plan.
Buying the Right 56K Modem
Buying a 56K modem, also known as a dial-up modem or analog modem, can be confusing. There are several different form factors and processor options to choose from.
For example, should you buy a PCI Modem, a USB Modem, or a Serial Modem? What is the difference between USB 1.0 and USB 2.0? Do you need a controller-based modem, a controller-less modem, or a soft modem?
This brief tutorial will explain the different modem options available to help you choose the correct modem for you!
Hardware Modems, DSP-controlled Modems, and Soft Modems 56K modems come with three different processor types:
* Hardware modems, also known as a "controller modems" or "hardware-controlled modems"
* DSP-based modems, also known as a "controller-less modems"
* Software-based modems, also known as "softmodems" or "win modems"
Of these three types, hardware modems are the most powerful. DSP-based modems are the second most powerful, and softmodems are the least powerful.
In order to send and receive data over the Internet or a network, modems have to process outgoing and incoming data streams. Hardware-based modems have special hardware chips onboard that do most of this processing. Because of this, hardware-based modems do not have to rely on sending information to and from the computer’s central processor, which can slow down transmission speeds and place a heavy drain on the computer for performing other tasks.
DSP modems have some of the processing capability of hardware modems, but not all. As a result, they are faster than softmodems but not as fast as hardware modems.
Softmodems must rely almost entirely on the computer’s CPU to process the data. As a result, they are the slowest modems and place the greatest burden on the CPU, which may slow down other applications running on your PC.
How you are going to use the modem generally determines which is the best processor type for you:
* Hardware Modem: If you will use your modem daily for several hours or more you should most likely buy a hardware-based modem.
* DSP Modem: If you plan to use your modem daily for an hour or more then a DSP modem would be the best choice.
* Softmodem: If you plan to use your modem for simple Internet access a few times per week, a softmodem is probably the most suitable.
You should also consider your computer’s processor speed. In general, the slower your computer’s central processor is, the more powerful a modem you should purchase. This is because less powerful modems put more of a strain on the computer’s own processor. So you should only use a weaker modem (softmodem) if you have a fast central processor. You can check your processor’s speed by consulting the documentation for your PC. You can also check within Windows by selecting "Properties" on the "My Computer" icon.
Here are some general guidelines:
* 300 MHz or less: A hardware controlled modem would be best.
* 300 MHz - 1.0 GHz: DSP controlled modem would be best.
* Over 1.0 GHz: Softmodem would be acceptable.
Form Factor: USB Modem, External Serial Modem, PCI Modem, ISA Modem, PCMCIA Modem
56K modems come in 5 different form factors:
1. USB Modem (external)
2. External Serial Modem
3. PCI Modem (internal)
4. ISA Modem (internal)
5. PCMCIA Modem or Laptop Modem (external)
To purchase the correct form factor, you should consider what options are available for your computer, the performance required, and the ease or difficulty of the installation.
1. USB Modem: If you have a USB port available (either USB 1.0, USB 1.1, or USB 2.0) you might consider a USB modem. They are the easiest modems to install, since they do not require you to open your computer case. USB modems can usually be found in DSP and hardware-controlled versions.
2. External Serial Modems: Like USB modems, serial modems are external and easy to install. They are usually hardware controlled and offer excellent performance.
3. PCI Modems: These are the best-selling modems, and are generally the kind of modem that comes installed a new machine. PCI modems come as either DSP modems or softmodems. You should only purchase a PCI modem if you are comfortable opening your PC case and installing a new PCI card.
4. ISA Modems: These are also internal modems. To use an ISA modem, your PC must have an available ISA slot. These slots or usually only found on older PCs. Consult your system documentation to verify your slot type. These are usually hardware controlled modems, sometimes DSP-based.
5. PCMCIA Modems or Laptop Modems: This is a "card"-type modem that can be used only with a laptop. If you have both a laptop and a desktop PC, you might want to purchase a USB modem instead, since it can be used with either type. For simplicity and ease in traveling, a PCMCIA modem is the best choice.
Modem Vendors: Diamond Multimedia, Best Data Products, U.S. Robotics
Some of the leading vendors for 56K modems are Diamond Multimedia, Best Data Products, and U.S. Robotics.
* Diamond Multimedia’s SupraMax modems have been a leading brand of modems for more than a decade.
* Best Data Products has been offering high quality 56K modems for over 20 years. Their SmartOne modems are known for their value and durability.
For example, should you buy a PCI Modem, a USB Modem, or a Serial Modem? What is the difference between USB 1.0 and USB 2.0? Do you need a controller-based modem, a controller-less modem, or a soft modem?
This brief tutorial will explain the different modem options available to help you choose the correct modem for you!
Hardware Modems, DSP-controlled Modems, and Soft Modems 56K modems come with three different processor types:
* Hardware modems, also known as a "controller modems" or "hardware-controlled modems"
* DSP-based modems, also known as a "controller-less modems"
* Software-based modems, also known as "softmodems" or "win modems"
Of these three types, hardware modems are the most powerful. DSP-based modems are the second most powerful, and softmodems are the least powerful.
In order to send and receive data over the Internet or a network, modems have to process outgoing and incoming data streams. Hardware-based modems have special hardware chips onboard that do most of this processing. Because of this, hardware-based modems do not have to rely on sending information to and from the computer’s central processor, which can slow down transmission speeds and place a heavy drain on the computer for performing other tasks.
DSP modems have some of the processing capability of hardware modems, but not all. As a result, they are faster than softmodems but not as fast as hardware modems.
Softmodems must rely almost entirely on the computer’s CPU to process the data. As a result, they are the slowest modems and place the greatest burden on the CPU, which may slow down other applications running on your PC.
How you are going to use the modem generally determines which is the best processor type for you:
* Hardware Modem: If you will use your modem daily for several hours or more you should most likely buy a hardware-based modem.
* DSP Modem: If you plan to use your modem daily for an hour or more then a DSP modem would be the best choice.
* Softmodem: If you plan to use your modem for simple Internet access a few times per week, a softmodem is probably the most suitable.
You should also consider your computer’s processor speed. In general, the slower your computer’s central processor is, the more powerful a modem you should purchase. This is because less powerful modems put more of a strain on the computer’s own processor. So you should only use a weaker modem (softmodem) if you have a fast central processor. You can check your processor’s speed by consulting the documentation for your PC. You can also check within Windows by selecting "Properties" on the "My Computer" icon.
Here are some general guidelines:
* 300 MHz or less: A hardware controlled modem would be best.
* 300 MHz - 1.0 GHz: DSP controlled modem would be best.
* Over 1.0 GHz: Softmodem would be acceptable.
Form Factor: USB Modem, External Serial Modem, PCI Modem, ISA Modem, PCMCIA Modem
56K modems come in 5 different form factors:
1. USB Modem (external)
2. External Serial Modem
3. PCI Modem (internal)
4. ISA Modem (internal)
5. PCMCIA Modem or Laptop Modem (external)
To purchase the correct form factor, you should consider what options are available for your computer, the performance required, and the ease or difficulty of the installation.
1. USB Modem: If you have a USB port available (either USB 1.0, USB 1.1, or USB 2.0) you might consider a USB modem. They are the easiest modems to install, since they do not require you to open your computer case. USB modems can usually be found in DSP and hardware-controlled versions.
2. External Serial Modems: Like USB modems, serial modems are external and easy to install. They are usually hardware controlled and offer excellent performance.
3. PCI Modems: These are the best-selling modems, and are generally the kind of modem that comes installed a new machine. PCI modems come as either DSP modems or softmodems. You should only purchase a PCI modem if you are comfortable opening your PC case and installing a new PCI card.
4. ISA Modems: These are also internal modems. To use an ISA modem, your PC must have an available ISA slot. These slots or usually only found on older PCs. Consult your system documentation to verify your slot type. These are usually hardware controlled modems, sometimes DSP-based.
5. PCMCIA Modems or Laptop Modems: This is a "card"-type modem that can be used only with a laptop. If you have both a laptop and a desktop PC, you might want to purchase a USB modem instead, since it can be used with either type. For simplicity and ease in traveling, a PCMCIA modem is the best choice.
Modem Vendors: Diamond Multimedia, Best Data Products, U.S. Robotics
Some of the leading vendors for 56K modems are Diamond Multimedia, Best Data Products, and U.S. Robotics.
* Diamond Multimedia’s SupraMax modems have been a leading brand of modems for more than a decade.
* Best Data Products has been offering high quality 56K modems for over 20 years. Their SmartOne modems are known for their value and durability.
Tuesday, May 5, 2009
Internal Modems
An internal modem is basically an external modem and serial port mounted upon a PC bus card. These are cheaper than external modems as they do not require a power supply or a chassis.
Internal modems work fine for remote serial console applications. They are especially attractive for computers at co-location sites, as those sites charge according to space and power consumption.
Check that your internal modem preserves its setting across a power cycle.
Ensure that the interrupt line and port address space used by the internal modem's serial port do not conflict with that used by any other pre-existing serial ports. Alternatively, ensure that the internal serial port can be disabled, freeing its interrupt line and port address space for use by the internal modem.
Be careful not to confuse an internal modem with a WinModem. An internal modem does not need a special device driver, but appears to Linux as a stardard serial port. Find out more here.
Internal modems work fine for remote serial console applications. They are especially attractive for computers at co-location sites, as those sites charge according to space and power consumption.
Check that your internal modem preserves its setting across a power cycle.
Ensure that the interrupt line and port address space used by the internal modem's serial port do not conflict with that used by any other pre-existing serial ports. Alternatively, ensure that the internal serial port can be disabled, freeing its interrupt line and port address space for use by the internal modem.
Be careful not to confuse an internal modem with a WinModem. An internal modem does not need a special device driver, but appears to Linux as a stardard serial port. Find out more here.
External Modems
External modems are communication devices that computers utilize to connect to public networks like the Internet. A modem that sits inside the computer is called an internal modem, while modems that sit exterior, are external modems.
The type of modem you require depends on the type of Internet access service you desire. There are two general categories: Basic dial-up service, and high-speed broadband service.
Basic Dial-Up (Internal and External Modems)
Traditionally, internal modems have been dial-up modems that connect to Internet service providers (ISPs) using an analog signal over a telephone line. Since telephones also use analog signals, phones and modems cannot share lines simultaneously. Dial-up is the slowest, but also the least expensive way to connect to the Internet.
External modems can also be dial-up modems, and if so, will be rated at a transfer rate of 56 kbps (kilobytes per second), like their internal twins. External modems are handy when there are no available internal slots, or if the modem needs to be shared between computers that are not networked. In this case an external modem connected to a desktop system, can easily be disconnected and connected to a different desktop, or even a laptop.
External modems for dial-up service are inexpensive and available everywhere computers are sold. They are easy to setup, come with instructions, and most include fax capability at the software level. Recent versions of most operating systems recognize and load drivers for dial-up modems, which are plug-and-play devices.
High-speed Broadband (External Modems)
Most external modems today are not dial-up modems, but broadband modems. External modems designed for broadband service provide a different kind of Internet connection that is extremely fast, used with high-speed ISPs. Broadband modems typically have transfer rates from 1.5 — 8 mbps (megabytes per second), or higher.
DSL, FiOS, cable and satellite are different flavors of high-speed Internet. Normally ISPs selling broadband Internet access will provide their customers with external modems pre-configured to use with the service. Depending on the contract terms, the external modems might be leased with a small monthly charge, or provided free to use for the duration of the client's contract. High-speed modems are normally not internal.
External modems used for broadband service can be wired, or wireless. If wireless, a wireless network adapter must be installed in each computer that is to communicate with the modem. These adapters can be PCMCIA, or external devices that attach to the computer via the USB port.
DSL modems utilize the telephone line for sending digital signals rather than analog signals. Consequently, you can use the telephone while using DSL service. This is also true of FiOS service, which uses fiber optic lines in place of standard copper telephone lines. External modems used for high-speed cable service will not use the telephone line, but rather the cable TV line. Local cable companies provide cable Internet service, where available.
If interested in high-speed Internet service, do not shop for external modems without first selecting your ISP, as it will likely provide the broadband modem for you. Find out more here.
The type of modem you require depends on the type of Internet access service you desire. There are two general categories: Basic dial-up service, and high-speed broadband service.
Basic Dial-Up (Internal and External Modems)
Traditionally, internal modems have been dial-up modems that connect to Internet service providers (ISPs) using an analog signal over a telephone line. Since telephones also use analog signals, phones and modems cannot share lines simultaneously. Dial-up is the slowest, but also the least expensive way to connect to the Internet.
External modems can also be dial-up modems, and if so, will be rated at a transfer rate of 56 kbps (kilobytes per second), like their internal twins. External modems are handy when there are no available internal slots, or if the modem needs to be shared between computers that are not networked. In this case an external modem connected to a desktop system, can easily be disconnected and connected to a different desktop, or even a laptop.
External modems for dial-up service are inexpensive and available everywhere computers are sold. They are easy to setup, come with instructions, and most include fax capability at the software level. Recent versions of most operating systems recognize and load drivers for dial-up modems, which are plug-and-play devices.
High-speed Broadband (External Modems)
Most external modems today are not dial-up modems, but broadband modems. External modems designed for broadband service provide a different kind of Internet connection that is extremely fast, used with high-speed ISPs. Broadband modems typically have transfer rates from 1.5 — 8 mbps (megabytes per second), or higher.
DSL, FiOS, cable and satellite are different flavors of high-speed Internet. Normally ISPs selling broadband Internet access will provide their customers with external modems pre-configured to use with the service. Depending on the contract terms, the external modems might be leased with a small monthly charge, or provided free to use for the duration of the client's contract. High-speed modems are normally not internal.
External modems used for broadband service can be wired, or wireless. If wireless, a wireless network adapter must be installed in each computer that is to communicate with the modem. These adapters can be PCMCIA, or external devices that attach to the computer via the USB port.
DSL modems utilize the telephone line for sending digital signals rather than analog signals. Consequently, you can use the telephone while using DSL service. This is also true of FiOS service, which uses fiber optic lines in place of standard copper telephone lines. External modems used for high-speed cable service will not use the telephone line, but rather the cable TV line. Local cable companies provide cable Internet service, where available.
If interested in high-speed Internet service, do not shop for external modems without first selecting your ISP, as it will likely provide the broadband modem for you. Find out more here.
Types of Modems
External vs. Internal Modems
* External Modem: This is a modem separated from the system unit in the computer case. It is connected to the serial port of the computer by means of a cable. It is connected to the telephone wall jack by another cable.
* Internal Modem: An internal modem is a circuit board (a modem card) that can be added to the system unit of the computer. It takes one of the expansion slots.
Standard vs. Intelligent Modems
* Standard Modems: Most modems used today are called standard modems. These modems are usually operated by commands entered from a microcomputer keyboard. Users control the functions (dialing, etc.) of a modem through the keyboard. Modems may use different command languages to control their functions, but most modems (called "Hayes compatible") use a popular language developed by a company "Hayes Microcomputer Products, Inc." The command ATDSX4, for example, indicates that pay attention (AT), dial stored telephone number (DS), and then display the progress of the call (X4).
* Intelligent Modems: Intelligent modems are also called advanced modems. These modems can accept new instructions and then respond to the commands while transmitting data and information. These can be done by microprocessor chips and internal read only memory (ROM) contained in the modem. Of course, these modems are more expensive.
Short-Haul and Wireless Modems
* Short-Haul Modems: Short- haul modems are devices that transmit signals down the cable through any COM1 port. They sometimes are called modem eliminators, because they do not require an external power source. They are also called line drivers that can send data for a distance of more than one mile. This type of modem can be used within or across several buildings in a company or a university campus.
* Wireless Modems: Wireless modems transmit the data signals through the air instead of by using a cable. They sometimes are called a radiofrequency modem. This type of modem is designed to work with cellular technology, and wireless local area networks. Wireless modems are not yet perfected, but the technology is rapidly improving. Find out more here.
* External Modem: This is a modem separated from the system unit in the computer case. It is connected to the serial port of the computer by means of a cable. It is connected to the telephone wall jack by another cable.
* Internal Modem: An internal modem is a circuit board (a modem card) that can be added to the system unit of the computer. It takes one of the expansion slots.
Standard vs. Intelligent Modems
* Standard Modems: Most modems used today are called standard modems. These modems are usually operated by commands entered from a microcomputer keyboard. Users control the functions (dialing, etc.) of a modem through the keyboard. Modems may use different command languages to control their functions, but most modems (called "Hayes compatible") use a popular language developed by a company "Hayes Microcomputer Products, Inc." The command ATDSX4, for example, indicates that pay attention (AT), dial stored telephone number (DS), and then display the progress of the call (X4).
* Intelligent Modems: Intelligent modems are also called advanced modems. These modems can accept new instructions and then respond to the commands while transmitting data and information. These can be done by microprocessor chips and internal read only memory (ROM) contained in the modem. Of course, these modems are more expensive.
Short-Haul and Wireless Modems
* Short-Haul Modems: Short- haul modems are devices that transmit signals down the cable through any COM1 port. They sometimes are called modem eliminators, because they do not require an external power source. They are also called line drivers that can send data for a distance of more than one mile. This type of modem can be used within or across several buildings in a company or a university campus.
* Wireless Modems: Wireless modems transmit the data signals through the air instead of by using a cable. They sometimes are called a radiofrequency modem. This type of modem is designed to work with cellular technology, and wireless local area networks. Wireless modems are not yet perfected, but the technology is rapidly improving. Find out more here.
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