+---------+--------------------------+-------+
| I/O Pin | Signal Name              | I / O |
+---------+--------------------------+-------+
|         |                          |       |
|   01    | + Adress/Data Bit 0      |  I/O  |
|   02    | + Adress/Data Bit 1      |  I/O  |
|   03    | + Adress/Data Bit 2      |  I/O  |
|   04    | + Adress/Data Bit 3      |  I/O  |
|   05    | + Adress/Data Bit 4      |  I/O  |
|   06    | + Adress/Data Bit 5      |  I/O  |
|   07    | + Adress/Data Bit 6      |  I/O  |
|   08    | + Adress/Data Bit 7      |  I/O  |
|   09    | + Adress Bit 8           |  I    |
|   10    | + Adress Bit 9           |  I    |
|   11    | + Interupt Request 4     |    O  |
|   12    | - I/O Read               |  I    |  
|   13    | + Reset                  |  I    |
|   14    | - Data Enable            |  I    |
|   15    | Ground                   |  GND  |
|   16    | + Adress Latch Enable    |  I    |
|   17    | Ground                   |  GND  |
|   18    | + Adress Enable          |  I    |
|   19    | Ground                   |  GND  |
|   20    | + 12 VDC                 |  PWR  |
|   21    | Ground                   |  GND  |
|   22    | Ground                   |  GND  |
|   23    | Ground                   |  GND  |
|   24    | Ground                   |  GND  |
|   25    | - 13 VDC                 |  PWR  |
|   26    | Ground                   |  GND  |
|   27    | - I/O Write              |  I    |
|   28    | + 5 VDC                  |  PWR  |
|   29    | Ground                   |  GND  |
|   30    | + High Z                 |  I    |
|         |                          |       |
+---------+--------------------------+-------+

  Figure 3-6. System Board Modem Connector