FIELD BULLETIN NUMBER 20
                                 June 1983

           TS 803: PATCH TO ALLOW RUNNING AN ETX/ACK TYPE PRINTER

        Install the following patch to alllow running the Version 1.0 and
        1.1 system diskettes with an ETX/ACK type printer.   Version  1.2
        system diskettes will run the ETX/ACK type printer without patch-
        ing.

        This  patch masks off the acknowledge byte of the ETX/ACK printer
        in the TS 803 BIOS.

        1.   Run SYSGEN,  entering 'A' for source drive,  and a  carriage
        return for destination drive.

        2.   Save the system image with 'SAVE 52 CPMxx.803',  where xx is
        your version of the CP/M.

        3.   Patch the following into the system  image  file  with  'DDT
        CPMxx.803'.    The  numbers  given  below  are  assumed  to be in
        hexidecimal:
        Address                  Before Patch          After Patch
           231A                      DD                     00
           231B                      A6                     E6
           231C                      02                     7E

        4.  Save the system image with 'SAVE 52 CPMxx.803'.

        5.  Run SYSGEN again, by entering 'SYSGEN CPMxx.803', then an 'A'
        for destination drive.

        6.   Reset the system.   There is no need to further  retain  the
        system image file.

        After  installing  the  patch,  follow instructions in the TS 803
        User's Manual for installing the printer.

           TS 803:OBTAINING INFORMATION ON Z80 STI CHIP

        The TS 803 modem port is controlled by a Mostek MK 3801  Z80  STI
        Serial  Timer  Interrupt  Controller chip.   This device contains
        three functions in a single package:

        1.  Priority Interrrupt Controller
        2.  Four-Channel Counter-Timer
        3.     USART   (Universal   Synchronous   Asynchronous   Receiver
        Transmitter)

        If you must program this device in your application programs, you
        may  obtain detailed information from the Mostek Technical Manual
        for the Serial Timer Interrupt Controller _(STI) _MK3801,  Mostek
        publication number 4420250.  The cost of this manual $1.00.
        Order from:

        UNITED TECHNOLOGIES MOSTEK
        1215 West Crosby Road
        Carrollton, TX  75006       Telephone:(214) 466-6000

        or from :

        MOSTEK BRUSSELS
        270-272 Avenue de Tervuren  (BTE21)
        B-1150 Brussels, Belguium    Telephone:     762.18.80