Lucent Technologies MLS-model Programming And Use Manual page 222

Feature Reference
Using
System Phone
1. If you want, lift the handset.
2. Press the programmed button and dial the two-digit system line number of
the idle line you want to access; or press
number.
If you did not lift the handset, the speaker comes on automatically.
Standard Phone
1. Lift the handset.
You hear intercom dial tone.
8
2. Dial
access.
5-112
and the two-digit system line number of the idle line you want to
i 8
and the two-digit line