AT&T Merlin II Installation And Maintenance Manual page 143

FIGURE 2-20 Installing the Feature Module.
Modifying the 517A7
Processor Module for
Square (Key)
O p e r a t i o n
Feature
module
Processor module
The MERLIN II system can be configured to operate
solely as a square (key) system. As such, every outside
line appears on the same button at each voice terminal. If
you have Processor Module 517A7, use the following
steps to modify it for square (key) operation:
1 Open the Processor Module case by releasing the
seven snaps located around the edges of its case
(Figure 2-21).
2 Notice the two headers marked "AA" on the module's
processor board. One header is located at the bottom
right of the module; the other header is located at the
center right. Do not touch the header at the bottom.
Installing the Control Unit 2-75