AT&T DEFINITY 555-230-223 - Manual (Page 37)

Installation
Keep in mind that the DEFINITY LAN Gateway system is data terminal
equipment (DTE), and the switch is data communications equipment (DCE).
Therefore, you may need to install a null modem to complete the DTE/DCE pair
when connecting the PC.
MFB Port Usage
The MFB Y-cable has two RS-232C connectors labeled Main/Port A and
Admin/Port B.
The administration and maintenance terminal should be connected to Admin/Port
B. Some system diagnostic messages, created only when the system is
initializing, are sent to Main/Port A. These additional messages are not useful
during normal operation of the system.
Perform one of the four Subtasks (7A, 7B, 7C, or 7D, depending on the
connection type) to connect a system-access terminal to Admin/Port B. Use
Worksheet B-1, Terminals/Modems, to determine which tasks to complete.
The descriptions of Tasks 7B, 7C, and 7D assume that you are connecting a
remote terminal to Admin/Port B. You can also use these tasks for a remote
connection to Main/Port A by substituting A for B in the descriptions.
Task 7A: Install a Terminal via a Direct
Connection
Refer to Figures 2-8, Installing a Terminal via Direct Connection, and 2-9,
Installing a Terminal via Direct Connection (DC Switch Only), while performing
this task.
2-18 Issue 1 January 1996