Panasonic EASA-PHONE KX-T2740 Operating Instructions Manual page 52

Selection of Line Mode Selectors
@ Usually-"A" position
"B" position is for PBX system (Low Volt).
a h cues,
[LINE MODE
@ If the line indicator remains on when you connect the unit to the
LINE 1 LINE2
telephone line and place the handset in the cradle (on-hook
condition), switch the selector to "B" from "A".
Ae*8 Ae*B
@ If the line indicator does not light when lifting the handset of
another telephone connected on the same line, confirm whether
the selector is set to "A" or not. If it is set to "B", switch to "A".
Select the proper position on each line.
suo
Example;
Connection to two normal telephone lines is O.K.
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