Phoneline Modems: Serial or USB?

For many years, we have debated the merits and demerits of internal and external dialup modems. An Internal modem is simpler to use. However, when it breaks down and needs to be replaced, we have to lift the cover off the CPU box.

The same is true if you want to use the same modem in more than one PC. An external modem is easier to move from one PC to another. Just unplug the data cable from the serial port at the back of one PC and insert the plug into the serial port of the other PC.

The drawback of an external modem is that it requires its own external power supply. That is why it usually comes with a power button. We may have to switch it on or off to save on electricity or to avoid overheating-which rarely happens, anyway. A more serious consideration is the price: An external modem, obviously, costs more than an internal modem. It is easy to see why.

The modem manufacturer has to add a housing for the PCB, a data cable and a power adapter, while an internal modem does not require any of these.

As to the protection against lightning, there is not much difference between the two. Both internal and external modems may be equipped with some protective circuit that will prevent-to a certain degree-the PCs from being damaged by lightning.

What about the speed? There is not much difference, either. Both of them use the serial I/O of the PC. If you are lucky enough to have a clean phoneline connection, you can get close to the maximum 56 Kbps with a V.90 modem.

Today, newer PCs and notebooks come with several USB ports. A USB connection allows almost 50 times faster traffic than a serial connection. Besides, a USB device can also get the power that it needs from the host PC or notebook via the USB cable. Understandably, the USB-based modems have begun to appear on the market.

One of them is the Integral Fax Modem USB 56K. Not much larger than a pack of cigarettes, it can be connected to and disconnected from the PC at any time, without forcing us to power down the computer. Just plug the included USB cable, install the right driver for your operating system, and you are set to surf the Internet. It does not have an LED like the serial external modem, but most users do not usually look at these lamps anyway.

Another example of USB modems is from Zoom, a company that has been selling quality modems for many years. Zoom's 3090 fax modem does have LEDs, and it has Zoom's ZoomGuard proprietary lightning protection.

Both the Integral and Zoom modems follow the newer ITU V.92 and V.44 standards, which allows the user to hold the Internet dialup connection while using the same line for a telephone conversation provided he has call-waiting service. Another big plus for an external USB dialup modem is that it can also be used with a Mac -- or even with Sony PlayStation. You will have to check for compatibility with PS2, though.

So, if you are looking for a new modem to replace your older one, you had better seriously consider the USB-based models. There are several others beside the ones made by Integral and Zoom, including ActionTec. Make sure they follow the V.92 and V.44 standards and have lightning protection. And, if you travel a lot, choose one that can be configured to suit the local phone company's specifications. -- Zatni Arbi