2500 SX/20 (250-4077) Addendum Faxback Doc. # 1112 HARD DRIVE ENHANCEMENTS The Tandy 2500 SX/20 Hard Drive includes an 85 MB Intelligent Drive Electronics (IDE) hard disk drive, a PS/2-style mouse, and a 2400 baud internal modem. This bulletin lists features, guidelines for use, and specifications for these system components. FEATURES This section describes some key features of the Tandy 2500 SX/20 Hard Drive system. 20 MHz INTEL 80386 SX MICROPROCESSOR The 80386 SX microprocessor provides Intel processing power at an enhanced processing speed of 20 MHz. If you choose to install a math coprocessor to further enhance the 80386 SX numerical processing capabilities, select a 20 MHz 80387 SX math coprocessor. CHANGING THE CPU SPEED--THE SPEEDSX UTILITY Your CPU supports two CPU clock speed settings, fast (20 MHz) and slow (10 MHz). Use the SpeedSX utility on MS-DOS 5.0 Disk 2 to choose either setting. To select the fast CPU speed, type speedsx fast and press ENTER at the MS-DOS prompt. To select the slow speed, type speedsx slow and press ENTER at the MS-DOS prompt. HARD DRIVE The features of the Tandy 2500 SX/20 Hard Drive make using the computer faster and easier. These features include: * Average Seek Time Less Than 18 Milliseconds--Enables you to quickly access the files stored on the drive. * Disk Caching System--Uses a 32 KB RAM buffer to enhance read/write performance and disk operations. * 85 MB Formatted Capacity--Provides space for installing additional applications and storing work files. The drive is preformatted at the factory. No modifications are required after you set up the computer. * Built-in IDE Hard Disk Controller--Saves the cost of a controller card and frees an expansion slot for other uses. * Automatic Head Parking--Secures the drive heads at power down for safety. This feature enables you to move the computer (when powered down) without damaging the hard drive. Do NOT move the computer when it is turned on. * Pre-installed Applications--Let you begin running applications immediately after setting up the system. America Online, Prodigy, and DeskMate, and MS-DOS 5.0 are installed on the hard drive at the factory. Refer to "Using the Hard Drive" section for more information. MODEM The modem enables you to communicate with other computers and bulletin board services (BBS) using a telephone line. The model lets you access the America Online and Prodigy information services for which the startup files are installed on the hard drive. Features of the modem include: * Hayes Compatibility--Enables you to use most communications software to control the modem settings. * High-Speed Transmission--Sends and receives data at up to 2400 bits per second (bps). * Direct Connection--Lets you plug your computer directly into a phone line. * Pulse (Rotary) or Touch-Tone Dialing--Enables you to connect to any U. S. telephone system. MOUSE The PS/2-style mouse enables you to move quickly around the screen to select text, graphics, and program functions. The mouse drivers mouse.com and mouse.sys are included on the hard drive. The drivers contain basic operating instructions that enable the mouse to work with your computer. The drivers also monitor the mouse position, obtain data from the mouse buttons, and display a text cursor or graphics pointer on the screen. Cursors and pointers are displayed only in those applications that include mouse support. Refer to "Using the Mouse" for information about loading the mouse drivers. GUIDELINES FOR USING THE 2500 SX/20 HARD DRIVE SYSTEM This section explains how to use the internal modem, hard drive, and mouse. USING THE HARD DRIVE Before you use the hard drive, use the MS-DOS dir command to look at the directories and files on the drive. NOTE: Make backup copies of the software that you use on the hard drive. Use the backup copies as you working diskettes and store the original diskettes in a safe place. Use the originals only if the files on your working diskette or hard drive are ever damaged. At the C:> prompt, type dir and press ENTER. A list of the directories on the hard drive is displayed. Use the chdir command to change to any directory and the dir command to review the files stored in a directory. The Prodigy software is not provided on diskette. Use the copy command to make a working copy of the files in the Prodigy directory. To change to the directory, type cd \prodigy. Insert a formatted, high-capacity (1.44 MB) diskette into the diskette drive. Type copy *.* a: to copy all files in the directory to the diskette. Each filename is displayed as the file is copied to the diskette. Keep the following guidelines in mind as you use your Tandy 2500 SX/20 Hard Drive: * Consult MS-DOS Help or an MS-DOS reference before using commands on the hard drive. Some commands, such as format and fdisk, affect the hard drive. Your hard drive was formatted at the factory; to format it again would destroy all files on the drive. * Perform regular backups of the files on your hard drive. use the MS-DOS backup command. * Follow the instructions in your application documentation when installing new programs on the hard drive. Many applications use a setup or install program for installation. Such applications can not be installed by copying the files directly to the drive. NOTE: There are two connectors on the drive cable that attaches the drive to the main logic board. If you install a second IDE (SmartDrive) hard drive in the computer, connect the remaining cable connector to the new drive. Refer to the Tandy 2500 SX User's Guide and the hard drive installation guide before installing a second drive. USING THE MODEM To prepare the modem for use, connect the modem to the telephone line as directed below: CONNECTING THE TELEPHONE LINE 1. Position one end of the phone cable with the plug's clip down. 2. Insert the plug into the modem jack on the adapter at the back of the computer. 3. Connet the other end of the phone cable to a modular phone jack. MODEM SOFTWARE Refer to the America Online, Prodigy, and DeskMate documentation included with your your computer for more information on accessing the modem with software. NOTE: If you use the modem with communications applications other than those included with the computer, specify COM2 as the communications port used by the modem. MODEM COMMANDS Data can be transmitted or received in communications mode. To send commands, use the escape code to switch to the command mode. An escape code is a sequence of characters than can be used to switch the modem from the communications mode to the command mode. The default escape code is: +++ Wait a few seconds for the modem to acknowledge the entry. The modem sends a return code of 0, which means OK. All commands must begin with AT, the attention command. You can type one or more commands after AT, bu the line length can not exceed 42 characters. A single letter command can be followed by a single digit option. The modem processes commands after you press ENTER in the order given. If you need to change a command line, use the backspace command to delete the letters before you press ENTER. The following tables list basic modem commands and return codes. COMMAND PARAMETER DESCRIPTION AT Attention. First command of each command line. D Dials the numbers that follow the command as specified by modifiers. P: Sets the modem to pulse dialing mode T: Sets the modem to tone dialing mode R: Reverses to answer mode after calls W: Wait for dial tone before dialing ; Return to command mode after dialing B 0 Select CCITT V.22 operation (1200 bps) 1* Select Bell 212A operation (1200 bps) E 0 Do not echo commands 1* Echo commands H 0* On hook (hang up) 1 Off hook M 0* Speaker off 1 Speaker on until carrier detected 2 Speaker always on 3 Speaker on until carrier detected, except during dialing * Indicated default parameter for command. RETURN CODE DESCRIPTION 0 OK. Completed processing a command line 1 CONNECT. C (jej-05/11/94)