Lucent Technologies MLS-model Programming And Use Manual page 309

Night Service Button (#503)
2. Enter the password.
The green light is on steady. Night Service is on.
To turn Night Service off:
1. Press the Night Service button at extension 10.
2. Enter the password.
The green light goes out. Night Service is off.
If a System Password is programmed, the green light next to the
button flashes; you must continue with Step 2.
If no System Password is programmed, the green light goes out and
Night Service is off.
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