RAD DATA COMMUNICATIONS
=======================

   MTM-20 (G.703 TERMINAL BLOCK, DC POWER)

   Card Type         Modem (synchronous)                          
   Chipset           Unidentified                                 
   Transfer Rate     32/64Kbps                                    
   Data Modulation   QAM                                          
   Data Bus          Serial                                       

<gopher://bitreich.org/I/th99/t/P-R/52189-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   |      Function       |    Label    |   Function   |  Label  |
   |------------------------------------------------------------|
   | DC power in                   |   CN1    | Analog   | SW2  |
   |                               |          | loopback |      |
   |                               |          | test     |      |
   |                               |          | switch   |      |
   |-------------------------------+----------+----------+------|
   | Line out (see pinout below)   |   SC1    | Remote   | SW3  |
   |                               |          | digital  |      |
   |                               |          | loopback |      |
   |                               |          | test     |      |
   |                               |          | switch   |      |
   |-------------------------------+----------+----------+------|
   | G.703 port (see pinout below) |   SC2    | Test     | SW4  |
   |                               |          | pattern  |      |
   |                               |          | switch   |      |
   |-------------------------------+----------+----------+------|
   | Local digital loopback test   |   SW1    |          |      |
   | switch                        |          |          |      |
   |------------------------------------------------------------|
   |      Note: Modem can be made to perform self-test by       |
   |      holding down SW2 and SW4. The DCD, TEST, and SQ LEDs  |
   |      should go on, and the RD LED should go off.           |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                         SC1 PINOUT                         |
   |------------------------------------------------------------|
   |    Function     | Terminal |    Function     |  Terminal   |
   |------------------------------------------------------------|
   | Ground                |    1     | Not used         |  5   |
   |-----------------------+----------+------------------+------|
   | Not used              |    2     | Transmit line    |  6   |
   |-----------------------+----------+------------------+------|
   | Receive line          |    3     |   Transmit line  |  7   |
   |-----------------------+----------+------------------+------|
   | Receive line          |    4     |                  |      |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                         SC2 PINOUT                         |
   |------------------------------------------------------------|
   |      Function      | Terminal |   Function    |  Terminal  |
   |------------------------------------------------------------|
   | Transmit line             |    1    | Receive line  |  4   |
   |---------------------------+---------+---------------+------|
   |   Transmit line           |    2    | Ground        |  5   |
   |---------------------------+---------+---------------+------|
   | Receive line              |    3    |               |      |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |                Setting                 | Label | Position  |
   |----------------------------------------+-------+-----------|
   | i DCD forced high                      |  JP3  | Pins 3 &  |
   |                                        |       | 4 closed  |
   |----------------------------------------+-------+-----------|
   | DCD normal                             |  JP3  | Pins 1 &  |
   |                                        |       | 2 closed  |
   |----------------------------------------+-------+-----------|
   | i Signal ground connected to chassis   |  JP4  | Pins 1 &  |
   | ground                                 |       | 2 closed  |
   |----------------------------------------+-------+-----------|
   | Signal ground not connected to chassis |  JP4  | Pins 2 &  |
   | ground                                 |       | 3 closed  |
   |----------------------------------------+-------+-----------|
   | FIFO connected to transmit line        |  JP6  | Pins 1 &  |
   |                                        |       | 2 closed  |
   |----------------------------------------+-------+-----------|
   | FIFO connected to receive line         |  JP6  | Pins 2 &  |
   |                                        |       |  3 closd  |
   |----------------------------------------+-------+-----------|
   | i Line speed set to 64Kbps             |  SW5  | Position  |
   |                                        |       |     4     |
   |----------------------------------------+-------+-----------|
   | Line speed set to 32Kbps               |  SW5  | Position  |
   |                                        |       |     3     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                       TRANSMIT LEVEL                       |
   |------------------------------------------------------------|
   | Setting  |  JP5/A  |  JP5/B  |  JP5/C  |  JP5/D  |  JP5/E  |
   |----------+---------+---------+---------+---------+---------|
   |  i 0dBm  | Closed  |  Open   |  Open   |  Open   |  Open   |
   |----------+---------+---------+---------+---------+---------|
   |  -3dBm   |  Open   | Closed  |  Open   |  Open   |  Open   |
   |----------+---------+---------+---------+---------+---------|
   |  -6dBm   |  Open   |  Open   | Closed  |  Open   |  Open   |
   |----------+---------+---------+---------+---------+---------|
   |  -9dBm   |  Open   |  Open   |  Open   | Closed  |  Open   |
   |----------+---------+---------+---------+---------+---------|
   |  -12dBm  |  Open   |  Open   |  Open   |  Open   | Closed  |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                        CLOCK SOURCE                        |
   |------------------------------------------------------------|
   |          Setting           |              JP1              |
   |----------------------------+-------------------------------|
   |         i Internal         |       Pins 1 & 2 closed       |
   |----------------------------+-------------------------------|
   |          External          |       Pins 3 & 4 closed       |
   |----------------------------+-------------------------------|
   |          Received          |       Pins 5 & 6 closed       |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                        LINE LENGTH                         |
   |------------------------------------------------------------|
   |              Setting              |          JP2           |
   |-----------------------------------+------------------------|
   |             i 0-10Km              |   Pins 3 & 4 closed    |
   |-----------------------------------+------------------------|
   |              7-13Km               |   Pins 1 & 2 closed    |
   |-----------------------------------+------------------------|
   | Auto select (not yet implemented) |   Pins 5 & 6 closed    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     DIAGNOSTIC LED(S)                      |
   |------------------------------------------------------------|
   | LED  | Color  |  Status  |            Condition            |
   |------+--------+----------+---------------------------------|
   | PWR  | Green  |    On    |           Power is on           |
   |------+--------+----------+---------------------------------|
   | PWR  | Green  |   Off    |          Power is off           |
   |------+--------+----------+---------------------------------|
   | RTS  | Yellow |    On    |       RTS signal is high        |
   |------+--------+----------+---------------------------------|
   | RTS  | Yellow |   Off    |        RTS signal is low        |
   |------+--------+----------+---------------------------------|
   |  TD  | Yellow |    On    |    DSU is transmitting SPACE    |
   |------+--------+----------+---------------------------------|
   |  TD  | Yellow |   Off    |     DSU is not transmitting     |
   |------+--------+----------+---------------------------------|
   |  TD  | Yellow | Blinking |    DSU is transmitting data     |
   |------+--------+----------+---------------------------------|
   |  RD  | Yellow |    On    |     DSU is receiving SPACE      |
   |------+--------+----------+---------------------------------|
   |  RD  | Yellow |   Off    |      DSU is not receiving       |
   |------+--------+----------+---------------------------------|
   |  RD  | Yellow | Blinking |      DSU is receiving data      |
   |------+--------+----------+---------------------------------|
   | DCD  | Yellow |    On    |     Carrier signal detected     |
   |------+--------+----------+---------------------------------|
   | DCD  | Yellow |   Off    |   Carrier signal not detected   |
   |------+--------+----------+---------------------------------|
   | TEST |  Red   |    On    |       DSU is in test mode       |
   |------+--------+----------+---------------------------------|
   | TEST |  Red   |   Off    |     DSU is not in test mode     |
   |------+--------+----------+---------------------------------|
   |  SQ  | Yellow |    On    |     Signal quality is good      |
   |------+--------+----------+---------------------------------|
   |  SQ  | Yellow | Blinking | Signal quality is poor or test  |
   |      |        |          |     pattern contains errors     |
   +------------------------------------------------------------+