We haven't discussed laptop computers and mobile communicating in any of our articles as yet. Today's laptops are powerful enough to be the only computer one needs at home/business/on the road. We will attempt to describe characteristics to look for in a laptop. The description will cover a range of opportunities. Future articles will get to the details of the purchase decision. 

Laptop Descriptions

My unit contains a 200 MB hard disk and four MB RAM. Today's 486 units use 350 to 810 MB hard disks. The Pentium units use 720 to 1.1 GB hard disks. Today's 486 Color Dual Scan units tend to have four MB RAM installed. The Color Active and Pentium units tend to have eight MB RAM installed. PCMCIA memory cards which contain four MB, eight MB, sixteen MB, etc., are used to upgrade one's laptop. 

 Most laptops use Liquid Crystal Display (LCD) panel technology. There are two types of LCD displays, Color Dual Scan and Color Active. And there are still a few Monochrome LCD displays available in the really cheap units. Dual Scan and Active describe how the LCD works and represents a cost factor. Dual Scan is the less costly of the two technologies and uses horizonal and vertical electrodes to charge each point of the screen for brightness. Color Active is the more costly of the techniques. 

 Dual Scan 486 DX2/50 MHZ units range in price from $1,798.00 to $2,550.00. Dual Scan 486 DX4/75 MHZ units range in price from $1,954.00 to $3,899.00. Hard disk size and RAM affect this price range greatly. Pentium units range from $2,847.00 to $5,199.00 for the same reasons. Both LCD types provide Video Graphics Array (VGA) displays by using the industry-standard VGA adapaters to support VGA-compatible software. Additionally, most laptops are capable of outputting to an external color VGA monitor by connecting to the video output port. 

 Docking stations or port replicators are also available to provide connection points to full size monitors, printers, and keyboards. Connection to these devices provides power, networking connections, full size monitors, home printers, large storage dirves, and other office facilities. Laptops which connect to these devices can be the only computer needed. 

 Other than the LCD displays and size, laptops function just like other PC computers with one further exception. Most laptops utilize an I/O technology standard from the Personal Computer Memory Card International Association, the PCMCIA card. Most vendors have agreed to follow these standards in the design and manufacture of their laptops. This technology standard specifies the design of credit card size I/O and memory devices which plug into slots in these laptops. Most laptops accept one or more of these PCMCIA cards (PC Cards) for such functions as modems, memory expansion, network connectors, removable hard disks, SCSI, multimedia, encryption, and multifunction. Typically, a laptop with this technology consists of the PCMCIA function card, controller integrated circuitry, and control card services software. The card services software is able to control more than one PCMCIA card and must be set up to do each function. The computer manufacturers design one or more PCMCIA slots into their laptops in order to accept these I/O devices. Most designs include one slot for memory and at least one slot for I/O and hard disk functions. The slot usually is designed to take the thickest card, ie., Type III. The manufacturer may include connections for two Type II cards in the laptop case slot. The connections are stacked together. 

 These PCMCIA slots correspond to a thickness standard which specifies a design Type, ie., Type I, Type II, Type III and Toshiba Type IV. Type I cards are usually memory cards and are 3.3 mm thick. Type II cards are I/O cards for fax, modems, SCSI, and LAN and are 5.0 mm thick. Type III and IV cards are for ATA (AT Attachment) purposes, such as hard disks, and are 10.5 mm plus thick. The connection pin-outs for all three Types meet the same design criteria so that a Type II or Type III card will fit into the slot in a connection, excepting the fact that Type I memory cards usually have their own slot. The current Standard which has been implemented 2.1. Nearly all vendors follow this standard in their manufacture. 

PCMCIA Hardware

 The actual PCMCIA standards provide a set of services and functions including hardware and software. An integrated circuit chip set is placed on the main bus within the architecture of the laptop motherboard for control purposes. Hardware components also include the socket and card. The socket holds the card in place so that the card properly mates with the socket pins. There are 68 pins in two rows of 34 each. Each pin transmits or receives the control signals which are required for operation of the I/O device. The third hardware component consists of the PCMCIA cards themselves. 

 Several functions are accomplished within the PCMCIA software including card type identity, specifying socket services to be conducted, low level API details for Intel 80x86 CPU sturcture, and card services for what is to be done. Finally, the client software, ie., the communications program, etc., is run through this structure. 

PCMCIA Card Functions

 ATA PC Cards are usually hard disks. They can be miniature rotating, magnetic drives or solid-state hard disks. The rotating capabilities provide drives with up to 340 MB capacity. The solid-state, ie., "bubble memory" hard disks do not hold as much capacity, but are extremely fast in data transfer. 

 Serial PC Cards are usually those which are configured to respond to the standard serial communicaiton ports. Fax-modems and other serial port devices which are mapped to serial ports are included. Cellular modems are available which allow connection via one's cellular telephone. 

 LAN or network PC Cards are those which are used to support eithernet or Token Ring networking software. 10base-T, 10base2, or combination network / modems are available. 3270 emulation network cards are available as well as wireless network cards. Integrated Services Digital Network (ISDN) multichannel high-bandwidth digital telephone connections which provide connection capabilities are beginning to be adapted. 

 Small Computer System Interface (SCSI) connector cards provide connections to hard disk drives, CD-ROM , and tape drives. Global Positioning System (GPS) cards provide connections with the electronic global positioning system receivers and are capable of pinpointing one's earth position very accurately. This data can be integrated into map software programs which provide actual earth location in real time. 

 Multimedia PC Cards connect sound and video from a varity of locations. CD-ROM cards capture the full sound and visual effects of the CD-ROM. Video cards connect cameras and camcorders. 

 Encryption cards enable the ability to create encryted data for local storage and remote transmission. Multifuction cards mix fax/modems with network capability. 

JOHN WOODY IS A TELECOMMUNICATIONS CONSULTANT SPECIALIZING IN SMALL BUSINESS COMMUNICATIONS, NETWORKS, AND INTERNET BUSINESS TRAINING.