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       # SCIENTIFIC MICRO SYSTEMS, INC.
       
          OMTI 3120A, OMTI 3127A
       
          +------------------------------------------------------------+
          |------------------------------------------------------------|
          | Data bus:     | 50-pin SCSI interface                      |
          |---------------+--------------------------------------------|
          | Size:         | 4" x 5.75"                                 |
          |---------------+--------------------------------------------|
          | Hard drive    | Up to two ST506/412 MFM drives in 3120A,   |
          | supported:    | and up to two                              |
          |               |                                            |
          |               | ST506/412 RLL 2,7 drives in 3127A          |
          |---------------+--------------------------------------------|
          | Floppy drives | None                                       |
          | supported:    |                                            |
          +------------------------------------------------------------+
       
   IMG IMG 1
          
       
          +------------------------------------------------------------+
          |                        CONNECTIONS                         |
          |------------------------------------------------------------|
          |                 Function                 |    Location     |
          |------------------------------------------+-----------------|
          | 50-pin SCSI interface                    |       J1        |
          |------------------------------------------+-----------------|
          | 34-pin MFM disk control connector        |       J2        |
          |------------------------------------------+-----------------|
          | 20-pin data cable connector              |       J3        |
          |------------------------------------------+-----------------|
          | 20-pin data cable connector              |       J4        |
          |------------------------------------------+-----------------|
          | DC power connector                       |       J10       |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                        SCSI ADDRESS                        |
          |------------------------------------------------------------|
          |    SCSI ID    |      W1      |      W2      |      W3      |
          |---------------+--------------+--------------+--------------|
          | »  |    0     |     open     |     open     |     open     |
          |----+----------+--------------+--------------+--------------|
          | »  |    1     |    closed    |     open     |     open     |
          |----+----------+--------------+--------------+--------------|
          | »  |    2     |     open     |    closed    |     open     |
          |----+----------+--------------+--------------+--------------|
          | »  |    3     |    closed    |    closed    |     open     |
          |----+----------+--------------+--------------+--------------|
          | »  |    4     |     open     |     open     |    closed    |
          |----+----------+--------------+--------------+--------------|
          | »  |    5     |    closed    |     open     |    closed    |
          |----+----------+--------------+--------------+--------------|
          | »  |    6     |     open     |    closed    |    closed    |
          |----+----------+--------------+--------------+--------------|
          | »  |    7     |    closed    |    closed    |    closed    |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                 USER CONFIGURABLE SETTINGS                 |
          |------------------------------------------------------------|
          |             Function              |   Location   | Setting |
          |-----------------------------------+--------------+---------|
          | » | SCSI parity enabled           |      W4      | closed  |
          |---+-------------------------------+--------------+---------|
          | » | SCSI parity disabled          |      W4      |  open   |
          |---+-------------------------------+--------------+---------|
          | » | Factory configured - do not   |   W12/1-3    |   N/A   |
          |   | alter                         |              |         |
          |---+-------------------------------+--------------+---------|
          | » | Factory configured - do not   |   W13/1-3    |   N/A   |
          |   | alter                         |              |         |
          |---+-------------------------------+--------------+---------|
          | » | Factory configured - do not   |   W14/1-2    |   N/A   |
          |   | alter                         |              |         |
          |---+-------------------------------+--------------+---------|
          | » | TRMPWR supplied by board      | W15/pins 1 & | closed  |
          |   | (3127A)                       |      2       |         |
          |---+-------------------------------+--------------+---------|
          | » | TRMPWR supplied by SCSI bus   | W15/pins 2 & | closed  |
          |   | (3127A)                       |      3       |         |
          |---+-------------------------------+--------------+---------|
          | » | Factory configured - do not   |   W17/1-3    |   N/A   |
          |   | alter                         |              |         |
          |------------------------------------------------------------|
          | Note: Location of W15 pin 1 is unidentified.               |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                    SECTOR CONFIGURATION                    |
          |------------------------------------------------------------|
          |    Bytes/Sector    | Sector/Track  |    W5     |    W6     |
          |--------------------+---------------+-----------+-----------|
          | »  |      512      |      17       |   open    |  closed   |
          |----+---------------+---------------+-----------+-----------|
          | »  |      256      |      32       |  closed   |   open    |
          |----+---------------+---------------+-----------+-----------|
          |    |  512 (3120A)  |      18       |   open    |   open    |
          |----+---------------+---------------+-----------+-----------|
          |    |  532 (3127A)  |      17       |   open    |   open    |
          |----+---------------+---------------+-----------+-----------|
          | »  |     1024      |       9       |  closed   |  closed   |
          |------------------------------------------------------------|
          | Note: Location of W6 is unidentified.                      |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                 TERMINATION POWER - 3120A                  |
          |------------------------------------------------------------|
          |            Function             | W11/1  | W11/2  | W11/3  |
          |---------------------------------+--------+--------+--------|
          | » |  TRMPWR supplied by board   |  open  | closed | closed |
          |---+-----------------------------+--------+--------+--------|
          | » | TRMPWR supplied by SCSI bus | closed | closed |  open  |
          +------------------------------------------------------------+