AT&T System 25 - Manual (Page 123)

INSTALLATION
Stand-Alone Data Terminals
Data terminals and computers may be connected to the system through
ADUs or a Multiple Asynchronous Data Unit (MADU) without being linked to a
voice terminal. Depending on the data terminal that they connect to, some
ADUs may need supplementary power for proper operation. See Figures
2-42 and 2-43.
ADU Connections
1.
2.
3.
Unpack the ADU and examine for damage.
At the workstation, connect the ADU connector to the RS-232C
receptacle of the terminal or computer. Always tighten the screws
or other fasteners on this connection. If these connections are not
properly fastened, the Data Line CP port may be falsely busied out.
Connect a modular cord between the ADU Wall jack and the modular
wall jack.
2-98