Next time you're there, you should do them a mitzvah and put paper designation squares, with the line numbers, under the line key caps. The caps just pop off and on.

From the top, down:

SPKR
PRIV RLS (optional)
ICM 1
ICM 2
(blank)
LINE 4
LINE 3
LINE 2
LINE 1
HOLD


Arthur P. Bloom
"30 years of faithful service...15 years on hold"