Got my answer on this from an external source, but FYI:
16D LED Test
Procedure
1) Depress dial pad buttons 1,2, and 3 simultaneously (for 5 seconds) while plugging the line cord into the phone under test. Release all three buttons at the same time.
2) Depress station 101 buttons according to the matrix shown below:
Soft Keys
Key to Press Sound LCD MW Lamp LEDs
Exit Confirm. Tone PUSH = F12 None None
Softkey 1 “ PUSH = S1 None None
Softkey 2 “ PUSH = S2 None None
Softkey 3 “ PUSH = S3 None None
Softkey 4 “ PUSH = S4 None None
Help “ PUSH = F13 None None
Line Buttons
Key to Press Sound LCD MW Lamp LEDs
R1B1 Ring Tone PUSH = L1 None Green
R1B2 New Ring Tone PUSH = L2 " Green
R1B3 Ring Chime PUSH = L3 " Green
R1B4 Confirm. Tone PUSH = L4 " Green
R1B5 " PUSH =L5 " Green
R1B6 " PUSH = L6 " Green
R1B7 " PUSH = L7 " Green
R1B8 " PUSH = L8 " Green
R2B1 " PUSH = L9 " Green
R2B2 " PUSH = L10 " Green
R2B3 " PUSH = L11 " Green
R2B4 " PUSH = L12 " Green
R2B5 " PUSH = L13 " Green
R2B6 " PUSH = L14 " Green
R2B7 " PUSH = L15 " Green
R2B8 " PUSH = L16 " Green
Dial Pad
Key to Press Sound LCD MW Lamp LEDs
(Pattern for LEDs of
FEATURE, CONF,
SPKR, ANSWER)
Key 1 Confirm. Tone PUSH = D1 Green Green
Key 2 " PUSH = D2 Red Red
Key 3 " PUSH = D3 Off Off
Key 4 " PUSH = D4 Green Green
Key 5 " PUSH = D5 Red Red
Key 6 " PUSH = D6 Off Off
Key 7 " PUSH = D7 Green Green
Key 8 " PUSH = D8 Red Red
Key 9 " PUSH = D9 Off Off
Key * " PUSH = D* Green Green
Key 0 " PUSH = D0 Red Red
Key # " PUSH = D# Off Off
Function Keys
Key to Press Sound LCD's MW Lamp LEDs
RECALL Confirm. Tone PUSH = F4 Don’t Care N/A
FEATURE " PUSH = F5 “ GREEN
CONF " PUSH = F2 " GREEN
MIC PUSH – F9 RED
REDIAL " PUSH = F1 " LK1-4 RED
ANSWER " PUSH = F6 " GREEN
SPEAKER None PUSH = F7 " GREEN
TRANSFER Confirm. Tone PUSH = F0 " LK5-8 RED
HOLD " PUSH = F3 " LK1-4 OFF
VOL. UP None LCD DARK Amber No change
VOL. DOWN " LCD BLANK Don’t Care LK1-16 GREEN
VOL. DOWN “ “ “ “ RED
VOL. DOWN “ “ “ “ OFF
DIRECTORY Confirm. Tone F11 “ Don’t Care
MESSAGE “ F10 “ “ “