    AST RESEARCH, INC.           TECHNICAL BULLETIN # 0964              7-27-94

                                   ADVANTAGE! MODEM NOISE

    PROBLEM:        AST-built modem, (P/N 202626-001), which interfaces with the
                    Sound Blaster card for voice mail compatibility in Advantage!
                    systems, produces a great deal of system noise audible on the
                    speakers, if the volume is turned up all the way on both the
                    modem and the Sound Blaster.

    CAUSE:          Because the audio signal is amplified by both the modem and the
                    Sound Blaster card, it is possible to create the situation
                    where there is excessive amplification by having both volume
                    controls set at a high level.  This will cause system noise,
                    which is not normally audible, at an objectionable level.

    SYSTEMS
    AFFECTED:           AST                                              REVISION
                    PART NUMBER     DESCRIPTION                           LEVEL

                    501416-XXX      AP486DX2-50                             All
                    501417-XXX      AP486DX2-66                             All
                    501418-XXX      AP486SX33                               All
                    501419-XXX      AP486DX2-66                             All
                    501420-XXX      APL2486DX2-50                           All
                    501421-XXX      APL2486DX2-66                           All
                    501434-XXX      ADV486SX-33                             All
                    501438-XXX      ADV486DX2-50                            All
                    501445-XXX      AP486DX2-50                             All
                    501449-XXX      ADV486SX2-50                            All

    SOLUTION:       To adjust the sound on the sound board:

                    1. Run the sound file.
                    2. While the sound file is running, adjust the volume control
                       on the sound board to a comfortable level.

                    To adjust the sound on the modem:

                    1. Set the modem volume to the lowest level
                       (counter-clockwise).
                    2. Turn the volume control up a quarter turn (clockwise).

                    You may need to adjust the volume slightly during the next
                    incoming call.

                    If the problem is not resolved after following the above steps,
                    you may need to replace the printed circuit board assembly ISA
                    adapter on your system with revision E or higher (P/N
                    202626-001).  See FCN 0148 for more details.