Behind Switch Mode With Direct Outside Lines - AT&T MERLIN LEGEND System Reference Manual

Functional Description
Figure 4-6

Behind Switch Mode with Direct Outside Lines

Depending on business needs, any one (or a combination) of the following
direct outside lines can be added:
loop-start (basic, WATS, FX)
tie trunks
DS1 facility
The direct outside lines must be terminated on individual telephones and must
appear on the telephones' line buttons. For example, if the tie trunks are
assigned to buttons on telephones 1 and 2, the buttons on those telephones
appear as shown in Figure 4-7.
4-18 Modes of Operation