CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [367]
Figure 21-15 34-mm and 54-mm Express-Cards
ExpressCards connect to either the Hi-Speed USB 2.0 bus or a PCI Express bus. These differ phenomenally in speed. The amazingly slow-in-comparison USB version has a maximum throughput of 480 Mbps. The PCIe version, in contrast, roars in at 2.5 Gbps in unidirectional communication. Very nice!
Table 21-4 shows the throughput and variations for the parallel and serial PC Cards currently or soon to be on the market.
Software Support for PC Cards
The PCMCIA standard defines two levels of software drivers to support PC Cards. The first and lower level is known as socket services. Socket services are device drivers that support the PC Card socket, enabling the system to detect when a PC Card has been inserted or removed, and providing the necessary I/O to the device. The second and higher level is known as card services. The card services level recognizes the function of a particular PC Card and provides the specialized drivers necessary to make the card work.
Table 21-4 PC Card Speeds
In today’s laptops, the socket services are standardized and are handled by the system BIOS. Windows itself handles all card services and has a large preinstalled base of PC Card device drivers, although most PC Cards come with their own drivers.
* * *
NOTE ExpressCards don’t require either socket or card services, at least not in the way PC Cards do. The ExpressCard modules automatically configure the software on your computer, which makes them truly plug and play.
Single-Function Ports
All portable PCs and many PDAs come with one or more ports. You’d have a hard time finding a portable computing device that doesn’t have a speaker port, and this includes modern PDAs. My Apple iPhone functions as an excellent MP3 player, by the way, a feature now included with most PDAs and smartphones. Some portables have line in and microphone jacks as well. Laptops invariably provide a video port such as a VGA or DVI connection for hooking up an external monitor and a PS/2 port for a keyboard or mouse. Finally, most current portable PCs come with built-in NICs or modems for networking support. (See the “Modular Laptops” section later in this chapter for more on networking capabilities.)
Ports work the same way on portable PCs as they do on desktop models. You plug in a device to a particular port and, as long as Windows has the proper drivers, you will have a functioning device when you boot. The only port that requires any extra effort is the video port.
Most laptops support a second monitor via an analog VGA port or a digital DVI, HDMI, or DisplayPort port in the back of the box. With a second monitor attached, you can display Windows on only the laptop LCD, only the external monitor, or both simultaneously. Not all portables can do all variations, but they’re more common than not. Most portables have a special Function (FN) key on the keyboard that, when pressed, adds an additional option to certain keys on the keyboard. Figure 21-16 shows a closeup of a typical keyboard with the Function key; note the other options you can access with the Function key, such as indicated on the F2 key. To engage the second monitor or to cycle through the modes, hold the Function key and press F2.
Figure 21-16 Laptop keyboard showing Function (FN) key that enables you to access additional key options, as on the F2 key
* * *
NOTE Although many laptops use the Function key method to cycle the monitor selections, that’s not always the case. You might have to pop into the Display applet in the Control Panel to click a checkbox. Just be assured that