With the rapid development of wireless networks, in terms of choosing network began to gradually shift from wired to wireless. The adoption of wireless networks not only makes the layout more concise, but provides a great convenience for the personal computer equipment and makes it more portable as well. It has become the current hot topic to join the wireless network camp. 

At present, there are mainly three kinds of external wireless card.

1. PCI interface, suitable for desktops;

2. PCMCIA interface, applicable to laptops;

3. USB interface, suitable for desktops and laptops.

Now, we will compare these three kinds of external wireless network card from the universality, stability, signal strength, cost.

Universality:

From the universality of view, because USB can be used in the desktop and laptop, USB is undoubtedly the best one, and when the signal is not strong enough, you can place the card in a window or door by using a USB extension cable.

Stability:

PCI interface network card, do not need to consider the power consumption, the size of PCB is also the largest, there is no problem of heat dissipation, so the stability of the best. 

PCMCIA interface network card, because need to consider the power consumption, the size of PCB is comparatively large, heat is also comparatively large, so stability of PCMCIA interface network card is inferior to PCI network card.

USB interface network card, the size of PCB is small, the largest heat, often because of excessive heat resulting in no Internet access.

Signal strength:

Due to an external antenna, the signal of PCI network card is the strongest; PCMCIA card is second only to PCI network card, the signal of USB network card is the worst.

Cost:

Because the space is small, USB network card using a crystal antenna, so the cost of it is the highest; PCMCIA network card and PCI card price is almost the same.

There are some factors need to be taken into consideration when purchase: the type of computer, the location of network card, signal conditions, price. Here we divided by computer type:

Desktop:

If it is close to the router and there is no signal problem, PCI interface network card is the best choice, because stability overrides everything. If the signal is poor, the first choice is USB interface card + USB extension cord. Second consideration is using PCI network card + external antenna.

Laptop:

If it is close to the router and there is no signal problem, PCMCIA interface network card is the best choice. If the signal is poor, the first choice is USB interface card + USB extension cord. 

Purchasing skills

Security:

The security of WLAN product is the most important, and in fact to protect data from interception and theft has also been WLAN users are most concerned about. Because the WLAN data transmission is completely exposed in mid-air, and a wide range of signal coverage, if the security is not good, the data of legitimate users can easily be intercepted and cracked by illegal users. Moreover, illegal users can also be disguised as legitimate users, and use the network resources with legitimate users, so that the interests of legitimate users will suffer losses. But the good news is that most of the networking products manufacturers have adopted encryption technology or to provide users with a full range of wireless security solutions, making the purpose of illegal users is difficult to succeed. Due to various factors, the current data encryption technology provided by different vendors and security solutions are different, which need to pay special attention in the purchase of wireless card. Some vendors offer multilevel security architectures, including the spread spectrum code and encryption technology, which provide the same level of security as wire networks without sacrificing performance through 40- and 128-bit Wired Equivalent Privacy (WEP) encryption methods.

Data transmission rate:

Wireless network card transfer speed depends largely on its use of the standard. At present, there are many wireless network specifications in use.

IEEE

Compared to other specifications, 802.11b has a great advantage, so now most of the wireless network products are used IEEE 802.11b specification. The theoretical transmission rate of 802.11b standard is 11Mbps, and the current majority of 802.11B-based WLAN products are also claim "rate of 11M", but this is just a rate under the fully ideal state. Except for the environmental factors affect, the actual use is also limited by product quality, the different product quality, the different transmission rate you have, which we should pay attention when buying.

Compatibility:

If you want to separately buy a network card from different manufacturers, compatibility need to be considered, generally speaking, most of WLAN products are produced based on IEEE802.11b specifications, so compliance with this specification can be compatible with each other, or it may not be compatible with each other.

To know the answer is not difficult, we just want to see whether the product passed the WI-FI certification, or that there is no WI-FI certificate on it. Wi-Fi certification is based on the IEEE802.11b standard for wireless LAN products, only certified products to ensure compatibility with other products based on 802.11B specifications.

Type of interface

The main interface type of the wireless network card is PCI, PCMCIA, USB etc. PCI interface is mainly used for desktop, because it is suitable for the built-in just like the interface of memory, and the PCMCIA interface can be used for laptops, USB interface is suitable for all types of computers, the transmission rate is fast, but not easy to carry. But what specific interface should be selected depends on the user's actual situation, such as some laptop users with PCMIA interface has been occupied by other devices, then the USB interface should be selected.

Usability

The installation and maintenance of some wireless network cards is very complex, it is difficult to complete the installation of drivers if there is no professional technical staff, while some wireless network cards is relatively simple, which we have to pay attention in the purchase. 

Cost

Compared to wired LAN products, WLAN prices are more expensive, which also restricts the rapid spread of WLAN. Currently, the different network cards have different price, you had better choose the products made by famous brands. Finally, it would be great that if you buy a complete set of products instead of purchasing separately, so that it will not only avoid compatibility issues, and equipment performance will play better, the solutions will be more perfect.