                            EPSON AMERICA, INC.
                         Product Support Bulletin

              Subject:Equity 486SX/25 PLUS Questions and Answers

   Date:  02/07/92                                     PSB No:  S-0137A
   Page(s):  1 of 10                                   Originator:  JAM/JD/MD

   GENERAL:

   Q1. What microprocessor does the Equity 486SX/25 PLUS use?

   A.   The Equity 486SX/25 PLUS utilizes the Intel 80486/25 SX
        microprocessor running at 8 or 25 MHz. Use of this CPU
        gives you 486 performance and compatibility in a 16-bit
        based computer architecture.

   Q2. What speed does the Equity 486SX/25 PLUS operate at?

   A.   The Equity 486SX/25 PLUS operates at either a 8Mhz or
        25Mhz processor speed. The default speed can be set by
        using the SETUP utility provided on the 486SX/25 PLUS
        REFERENCE diskette. The speed can be set by using the
        following keyboard commands:

          CTRL ALT + = 25 Mhz (High Speed)
          CTRL ALT - =  8 8Mhz ( Low Speed )
          CTRL ALT * =  Automatic speed mode set (This is when
                        the floppy disk drive is accessed.)

       There is also an ESPEED utility that can be run at the
       command prompt as follows:

          ESPEED/H   = Switch to high speed.
          ESPEED/L   = Switch to low speed.
          ESPEED/A   = Enables Automatic speed switching.

        If you run ESPEED with no parameters the following message
        is displayed:

          Epson Speed control utility Version X.XX
          Copyright (c) SEIKO EPSON CORP. 1990

          Usage: ESPEED [/H] [/L] [/A]
          /H= set high speed (no auto speed)
          /L= set low speed (no auto speed)
          /A= set auto speed


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                                             Page: 2 of 10

   Q3. What is the Auto Speed function?

   A.  The Equity 486SX/25 PLUS is capable of operating at 25Mhz
       or 8Mhz. Some copy-protected applications require the
       computer to run at 8Mhz while accessing the program
       diskette. By enabling the Auto Speed function, the
       computer automatically switches to 8Mhz when accessing the
       diskette drive. It then switches back to 25Mhz for optimal
       performance. See above procedure for setting the Auto
       Speed function.

   Q4. What BIOS does the Equity 486SX/25 PLUS use?

   A.  The Equity 486SX/25 PLUS BIOS is written specifically for
       the computer by Seiko-Epson Corp.

   Q5.  Does the Equity 486SX/25 PLUS have Cache Ram and can it be
        increased?

   A.   The Equity 486SX/25 PLUS utilizes an Intel A82385-25 Cache
        Controller with 32KB of high speed Static Ram. The Static
        Ram is surface mount soldered and there is no option for
        increasing the amount of Cache Ram.

   Q6.  can the Equity 486SX/25 PLUS support an 80487DX
        co-processor?

   A.   No, but 80487SX-25 support is available. The Equity
        486SX/25 PLUS has no socket for an optional 80487DX-25
        math co-processor.  Replacing the 804865X/25 processor
        with an Intel 80487SX co-processor will activate dual
        processor/co-processor support. This allows extra
        processing power for math intensive programs like Lotus
        1-2-3 or AUTOCAD.

   Q7.  Can the Equity 486SX/25 PLUS use option cards that are
        available for the IBM PC/AT?

   A.   The Equity 486SX/25 PLUS uses an AT-compatible ISA
        (Industry Standard Architecture) bus that enables you to
        install any of the various add-on products designed for
        IBM PC, XT or AT computer, such as: expanded memory, EGA
        or VGA video, internal modems and many more. It also
        supports all of the option boards manufactured by Epson
        for the EQUITY series. There are 6 standard I/O expansion
        slots (one with 8-bit bus and 5 with 16-bit bus). The
        16-bit slots will also accept most 8-bit compatible cards.
        The Equity 486SX/25 PLUS offers flexibility in tailoring
        the system to your needs.


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                                               Page: 3 oflO

   Q8. Are there any modem or fax products that can be used?

   A.  The Hayes Smartmodem 2400 and V-series 9600 Smartmodem
       (external) modems have been approved. The EverFax 24/96
       (internal) by Everex and the Intel SatisFAXtion fax
       products have been approved.

   Q9. Does the Equity 486SX/25 PLUS have a built-in mouse port?

   A.  Yes, it has a PS/2 compatible mouse port on the rear panel
       of the computer. The connector is a 6 pin mini DIN for an
       IRQ12 mouse or other device.

   Q10. Can any other Equity keyboards be used on this machine?

   A.   Equity Ie, PLUS Series keyboards can be used on the Equity
        486SX/25 PLUS.

   Q11. What is the logical assignment of Diskette Drives?

   A.   When the Equity 486SX/25 PLUS is configured with two
        diskette drives, it will boot from either diskette drive.
        If you boot the system from a diskette in the second
        diskette drive, normally the B drive, that drive becomes
        drive A and the first diskette drive, normally drive A,
        becomes drive B. This  assignment remains in affect until
        the system is reset with the reset switch, turned off, or
        is rebooted from the drive currently designated as drive B
        or the AFDD.EXE utility on the Reference Diskette is run
        (the use of AFDD is described later). Therefore, the drive
        assignments can be controlled in two ways:

        1.   Boot the computer from a diskette in the drive you
             want assigned as drive A.
        2.   Run the AFDD program to reverse the current drive
             letter assignment.

        The current logical drive assignments remain in effect
        when the system is rebooted from the hard disk by pressing
        CTRL- ALT-DEL. The drive assignments are lost if the
        system is turned off or reset with the reset button.

        To use the AFDD utility, type AFDD at the command prompt
        and the following message appears on the screen:


                                                 PSB No: S-0137A
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        Reassign FDD utility Version X.XX
        Copyright (c) SEIKO EPSON CORP. 1989

        New Assign           Present

          Drive A: 1.2MB <== 1.44MB
          Drive B: 1.44MB <== 1.2MB

        (S)et and Reboot, Any other key to Abort ?_

        If you press S, the drive letters are switched and the
        system reboots with the new assignments in effect.
        Pressing any other key aborts the operation and returns to
        the command prompt.

        NOTE: The diskette drive types shown in AFDD message vary
        with the types of drives installed. If another type of
        diskette drive is installed (360 KB or 720KB), the message
        is adjusted accordingly.

     Q12. What terminal emulation boards are compatible with the
          486SX/25 PLUS?

     A.   The following products have been tested and approved:

          3278/79 Emulation Adaptor          IBM
          IBM 5250 Board                     IBM
          TPMA/2                             DCA Inc.
          IRMA/3                             DCA Inc.
          SDLC                               IBM

     Q13. Does the 486SX/25 PLUS have a battery for the Real Time
          Clock?

     A.   The 486SX/25 PLUS uses the Dallas DS1287 RTC which
          incorporates an HD146818 compatible real-time clock with
          an internal battery.

     Q14. What video adapter comes with the 486SX/25 PLUS?

     A.   The 486SX/25 PLUS has built in VGA support that offers
          standard VGA ( 640 x 480 by 256 colors; interlaced mode ),
          extended VGA ( 800 x 600 by 16 colors; interlaced mode )
          and Super VGA resolutions up to 1024 x 768 by 16 colors,
          non-interlaced mode. 1Mb of Video Ram on system board.


                                               PSB No: S-0137A
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     Q15. Can the serial and parallel ports be disabled?

     A.   Yes, the parallel and serial ports can be disabled by
          running the SETUP program on the reference diskette and
          choosing DISABLE. The ROM BIOS has been enhanced to auto-
          detect serial and parallel port conflicts and will auto-
          configure the on-board ports to available LPT and COM
          addresses.

     Q16. How many internal device bays does the 486SX/25 PLUS have,
          and will it support a full-height device?

     A.   The 486SX/25 PLUS has 3 external bays; one 1/3 height and
          two half-height bays. Internal bays; two half-height
          vertical mount bays configurable as a vertical full-height
          bay.

     Q17. How many wait states does the 486SX/25 PLUS have?

     A.   At 25MHz, the system utilizes 0 wait states for RAM and
          ROM BIOS access on the motherboard. At 8MHz, all internal
          system memory cycles are 3 wait states.

     Q18. Are the wait states user selectable?

     A.   No, the 486SX/25 PLUS automatically inserts them when
          needed. However,  JP15 can be set to enable the early I/O
          channel ready signal, this adds one wait state to the cpu.

     Q19. How many jumpers are on the system board?

     A.   There are fifteen (15) jumpers on the system board:

          * Factory Default Setting

          Jumper 1: Coprocessor enable/disable.
                 A: 80487SX Coprocessor Installed
             *   B: 80486SX Processor Installed

          Jumper 2: NPX NMI signal\Coprocessor enable/disable
                 A: 80487SX Coprocessor Installed
             *   B: 80486SX Processor Installed

          Jumper 3: NPX FERR signal\Coprocessor enable/disable
                 A: 80487SX Coprocessor Installed
                 B: 80486SX Processor Installed

          Jumper 4: Embedded VGA video port enable/disable.

             *   A: Enables the built-in video port
                 B: Disables the built-in video port

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          Jumper 5: Power-on Password enable/disable.
                 A: Disables the power-on password.
              *  B: Enables the power-on password.

          Jumper 6: Monitor type color/monochrome.

              *  A: Color monitor is installed.
                 B: Mono monitor is installed.

          Jumper 7: Internal Mouse port IRQ12.

              *  A: Assigned to on board PS2 mouse port.
                 B: IRQ12 assigned to bus expansion slots.

          Jumper 15: IOCHRDY enable/disable.
                  A: Enables the early I/O channel ready signal.
              *   B: Sets a normal I/O ready signal.

          NOTE: J8 - J14 are Memory Size jumpers see Q28 on page 8 of 9.


HARD DISK DRIVES:

     Q20. what kind of hard disk drives are available for the
          486SX/25 PLUS?

     A.   As a factory configuration, the 486SX/25 PLUS is available
          with a 200MB, 3.5' hard disk (Conner CP-3204F, 16ms access
          time). This HDD offers a 1:1 interleave and uses an
          embedded controller with an IDE interface. When installing
          the 200MB drive, use Drive Type 64. These are the
          parameters:

     Cylinders = 683, Heads = 16, Sectors = 38, Landing Zone = 683
     ( No write precomp needed )

     Q21. What hard drive controller is used in the 486SX/25 PLUS?

     A.   The 486SX/25 PLUS uses a controller embedded on the hard
          drive. This controller connects to a Task File Host
          interface (IDE) that is integrated on the system board.

     Q22. Can the 486SX/25 PLUS use other hard disk drives and
          controllers?

     A.   Yes, third-party IDE AT-TYPE drives can be used on the
          embedded Host Interface. The Host Interface on the system
          board can be disabled by installing an appropriate Hard
          Drive Controller on the bus. An Auto-sense feature
          disables the on-board IDE port.  MFM, ESDI, SCSI third-
          party drives can then be utilized. 16-bit Hard Disk
          Controllers are recommended to maintain system
          performance.


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     Q23. What extended hard drive support is available in the ROM
          BIOS that comes with the Epson 486SX/25 PLUS?


     A.   The Seiko-Epson BIOS will directly support hard drives
          that range in size from lOMB to 153MB. There is direct
          support for the Seagate ST-251 as well as several ESDI
          drives. By providing this support for 3rd party hard disk
          drives, the Equity 486SX/25 PLUS has the capability to use
          most 3rd party 8-bit and 16-bit hard disk controllers.
          SCSI drives have their own controllers attached to the
          drive and should work correctly when attached to the bus
          with a SCSI host adapter.

          The 486SX/25 PLUS also has a User Definable parameter
          setting that allows you to set up hard disk drives that
          are not supported by the 486SX/25 PLUS Drive Type Table.
          In SETUP, a sub-menu lists the settings you can change for
          each drive: the number of cylinders (tracks), the number
          of read/write heads, the number of sectors, the
          precompensation cylinder, the landing zone (the cylinder
          on which you want to park the heads when moving the
          computer), and the total storage capacity in megabytes.
          This allows you to use hard drives much larger than 153MB.

FLOPPY DRIVES:

     Q24. What types of floppy disk drives will work on the 486SX/25
          PLUS?

     A.   The 486SX/25 PLUS comes standard with a 1/3 height 3.5"
          1.44MB floppy disk drive. There is built-in BIOS support
          for industry standard 5.25" half-height 360KB and 1.2MB,
          as well as 3.5" half-height 720KB and 1.44MB floppy
          drives. All four drive sizes are available from Epson.

     Q25. Will the 486SX/25 PLUS support 3 floppy disk drives?

     A.   Not directly, the Epson controller and ROM BIOS supports a
          maximum of two floppy drives.  Two floppy drives and an
          internal tape backup can be accessed from the front panel.

     Q26. Can the floppy disk controller be disabled?

     A.   No. The floppy disk controller is integrated in the system
          board and there are no jumpers to enable or disable it.


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MEMORY:

     Q27. How much memory is standard on the 486SX/25 PLUS?

     A.   The proprietary memory adapter card has 4Mb of Surface
          Mount DRAM (4Mb base). The card also has 12 SIMM (Single
          In-line Memory Modules) sockets to increase memory up to a
          maximum of 16Mb.

     Q28. How do I increase the memory of the 486SX/25 PLUS?

     A.   You can add SIMMs for increased on-board memory by
          installing them onto the proprietary memory adapter card
          in the 486SX/25 PLUS. Memory must be installed in a
          modular fashion. 4 SIMMS at a time compose a BANK. 3
          BANK's available from the 12 simm sockets. Each bank must
          utilize the same type of simm module for that bank. The
          system can utilize the follow types of SIMMs:

          256KB module = (256 Kilo-byte x 9 data-bits x 80 nano-seconds)
          1MB module = (1 Mega-byte x 9 data-bits x 80 nano-seconds)

          With added SIMMs, the total amount of on-board memory in
          the computer must be one of the following: 8, 9, 10, 12,
          or 16MB ( 4MB Base ):

          Memory Upgrade Configurations: 486SX/25 PLUS (4MB Base)

          U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11 U12  Total Memory **

          M  M  M  M                                  8MB
          M  M  M  M  k  k  k  k                      9MB
          M  M  M  M  k  k  k  k  k  k   k   k        10MB
          M  M  M  M  M  M  M  M                      12MB
          M  M  M  M  M  M  M  M  M  M   M   M        16MB

          Legend:
          M =    1Mb x 9 x 80ns SIMM
          k =  256kb x 9 x 80ns SIMM

          ** Total includes the standard 4MB of Base Memory


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          Jumper Setting For Extended Memory: JP8 - JP12

          JP8   JP9   JP10   JP11   JP12     TOTAL MEMORY

          B     B     B      B      A        4MB*  ( Base memory )
          B     B     B      A      A        8MB
          A     B     B      A      A        9MB
          A     A     B      A      A        10MB
          A     B     A      A      A        12MB
          A     A     A      A      A        16MB

          Jumper settings for base memory: JP13 & JP14

                   JP13 JP14                  Conventional Memory

                   A*   A*                    640KB
                   B    A                     512KB
                   B    B                     256KB

         * Factory settings

     Q29. What SiMMs should be used when adding memory to the 486sx/25 PLUS?

     A.   Use the Epson 1MB kit (A808091) or the 2MB kit (A808101),
          to extend the system memory. Should you need to use third
          party SIMM modules we recommend the following:

               Toshiba                 1 MBit x 9 70 nsec
               Matsushita              1 MBit x 9 70 nsec
               CDC Enterprises         1 MBit x 9 70 nsec
               Samsung                 1 MBit x 9 70 nsec
               Acculogic               1 MBit x 9 70 nsec

        **NOTE**

        The following SIMM chips do not work in the 486SX/25 PLUS:

               IBM             Panasonic
               Compaq          NMBS


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     SOFTWARE:


     Q30. What version of MS-DOS is provided with the 486SX/25 PLUS?

     A.   Epson MS-DOS is optional and the customer can choose
          between versions 3.30, 4.01 and 5.0.

     Q31. Is the 486SX/25 PLUS compatible with OS/2?

     A.   Yes, IBM OS/2 1.30 has been tested on the 486SX/25 PLUS.

     Q32. Will it support Unix and/or Xenix? Which Versions?

     A.   The Equity SX PLUS has been tested with Santa Cruz Operations
          Xenix 386 Rel. 2.3.4, Santa Cruz Operations Unix System V
          386 Rel. 3.20 and Interactive's Unix System V i386/i486 Rel 4.0.
