AT&T Merlin II Release 3 System Manual page 111

3-62 MERLIN II System Features
By default, the system assigns
Main Pool or Pool Access to the
first two line buttons. If you
assign a line or line pool, it
appears on the top button in the
second column.
FIGURE 3-10 The order in which lines and line pools are assigned to the 7406D
digital phones.